摘要：
Forests are essential for maintaining species diversity, stabilizing local and global climate, and providing ecosystem services. Exploring the impact of paleogeographic events and climate change on the genetic structure and distribution dynamics of forest keystone species could help predict responses to future climate change. In this study, we combined an ensemble species distribution model (eSDM) and multilocus phylogeography to investigate the spatial genetic patterns and distribution change of Quercus glauca Thunb, a keystone of East Asian subtropical evergreen broad-leaved forest. A total of 781 samples were collected from 77 populations, largely covering the natural distribution of Q. glauca. The eSDM showed that the suitable habitat experienced a significant expansion after the last glacial maximum (LGM) but will recede in the future under a general climate warming scenario. The distribution centroid will migrate toward the northeast as the climate warms. Using nuclear SSR data, two distinct lineages split between east and west were detected. Within-group genetic differentiation was higher in the West than in the East. Based on the identified 58 haplotypes, no clear phylogeographic structure was found. Populations in the Nanling Mountains, Wuyi Mountains, and the southwest region were found to have high genetic diversity. A significant negative correlation between habitat stability and heterozygosity might be explained by the mixing of different lineages in the expansion region after LGM and/or hybridization between Q. glauca and closely related species. The Nanling Mountains may be important for organisms as a dispersal corridor in the west-east direction and as a refugium during the glacial period. This study provided new insights into spatial genetic patterns and distribution dynamics of Q. glauca.
摘要：
Camellia oleifera is intensively cultivated in subtropical areas of China, exposing soils to various threats. However, the effect of long-term cultivation of Camellia oleifera on soil properties remains unclear and needs to be elucidated to improve soil and Camelia oleifera sustainable management. This study collected soil samples from different Camellia oleifera planting ages (2, 10, and 40 years) and performed aggregate fractionation and various analyses including physico-chemical, soil organic matter chemical composition analyses and a semi-quantitative analysis of organic carbon functional groups to investigate the effect of long-term cultivation of Camellia oleifera on soil macroaggregates (< 2 mm), mesoaggregates (2-0.25 mm) and microaggregates (< 0.25 mm) formation, soil organic matter (SOM), available nitrogen (AN), available phosphorus (AP), and available potassium (AK). The aggregate particles increased with increasing Camellia oleifera planting ages. Camellia oleifera long-term cultivation did not affected the soil pH in the aggregates, but significantly (P < 0.05) increased SOM concentration with the decrease in soil aggregate size. Similarly, Phenolics-C, ketones-C, lignins-C, and alkenes-C increased in soil aggregates with increasing cultivation time and are mainly distributed in < 0.25 mm fraction. The aromatics-C, carboxylic-C, aliphatic-C, and polysaccharides-C declined with increasing cultivation time and were mainly distributed in 2-0.25 mm and < 2 mm fraction. AN is abundantly distributed in 2-0.25 mm and its abundance increases with Camellia oleifera long-term cultivation. All soils were poor in AP and AK. Our study indicated that long-term cultivation of Camellia oleifera promoted soil aggregate formation, increased available nitrogen (AN), soil organic matter (SOM) and controlled the change of SOM chemical composition. However, our study recommended providing available phosphorus (AP) and available potassium (AK) in soil with Camellia oleifera cultivation for sustainable management.
摘要：
Achieving seedlessness in citrus varieties is one of the important objectives of citrus breeding. Male sterility associated with abnormal pollen development is an important factor in seedlessness. However, our understanding of the regulatory mechanism underlying the seedlessness phenotype in citrus is still limited. Here, we determined that the miR159a-DUO1 module played an important role in regulating pollen development in citrus, which further indirectly modulated seed development and fruit size. Both the overexpression of csi-miR159a and the knocking out of DUO1 in Hong Kong kumquat (Fortunella hindsii) resulted in small and seedless fruit phenotypes. Moreover, pollen was severely aborted in both transgenic lines, with arrested pollen mitotic I and abnormal pollen starch metabolism. Through additional cross-pollination experiments, DUO1 was proven to be the key target gene for miR159a to regulate male sterility in citrus. Based on DNA affinity purification sequencing (DAP-seq), RNA-seq, and verified interaction assays, YUC2/YUC6, SS4 and STP8 were identified as downstream target genes of DUO1, those were all positively regulated by DUO1. In transgenic F. hindsii lines, the miR159a-DUO1 module down-regulated the expression of YUC2/YUC6, which decreased indoleacetic acid (IAA) levels and modulated auxin signaling to repress pollen mitotic I. The miR159a-DUO1 module reduced the expression of the starch synthesis gene SS4 and sugar transport gene STP8 to disrupt starch metabolism in pollen. Overall, this work reveals a new mechanism by which the miR159a-DUO1 module regulates pollen development and elucidates the molecular regulatory network underlying male sterility in citrus.
作者：
Zhaohua Liu;Yong Lv*;Jiping Li;Xiaoyu Cao;Yiru Wang
期刊：
Forests,2024年15(4):633- ISSN：1999-4907
通讯作者：
Yong Lv
作者机构：
Research Center of Forestry Remote Sensing & Information Engineering, Central South University of Forestry & Technology, Changsha 410004, China;Key Laboratory of National Forestry and Grassland Administration on Forest Resources Management and Monitoring in Southern China, Changsha 410004, China;Faculty of Forestry, Central South University of Forestry and Technology, Changsha 410004, China;Author to whom correspondence should be addressed.;Hunan Provincial Key Laboratory of Forestry Remote Sensing Based Big Data & Ecological Security, Changsha 410004, China
通讯机构：
[Yong Lv] R;Research Center of Forestry Remote Sensing & Information Engineering, Central South University of Forestry & Technology, Changsha 410004, China<&wdkj&>Key Laboratory of National Forestry and Grassland Administration on Forest Resources Management and Monitoring in Southern China, Changsha 410004, China<&wdkj&>Faculty of Forestry, Central South University of Forestry and Technology, Changsha 410004, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
crown size;neighborhood effects;competition index;tree species diversity;tree growth
摘要：
Competition among trees for limited resources (e.g., sunlight, water, and nutrients) impacts their growth differently. Crown plays a crucial role in resource access for trees. However, uncertainties persist regarding crown size differences, tree growth, and tree competition levels between coniferous and broadleaf trees in mixed-age forests. We conducted a study on 3008 live trees across 28 plots in Hunan Province to measure individual crown size and tree growth increment. Introducing a new metric, the Crown Size Competition Index (CSCI), we assessed competition pressure among coniferous and broadleaf species in mixed-age forests. We examined the correlation between competition indices and tree growth increment while also investigating the influence of neighboring species diversity on tree competition. Our results revealed a significant negative correlation between the tree growth of Cunninghamia lanceolata (Lamb.) Hook.(CL) and Phoebe bournei (Hemsl.) Yang (PB) and the competition index. Increased competitive pressure on the focal tree corresponded to a decline in the growth of focal tree volume, with a more pronounced impact observed in PB compared to CL. The diversity of neighboring species contributed to variations in competition for the focal tree, with broadleaved species (PB) exerting a greater influence on the focal tree than coniferous species (CL). These findings underscore the competitive potential of PB in mature coniferous stands and advocate for the restoration of stratified mixes in CL broadleaf forests. Furthermore, our findings support the management strategies for the valuable tree species PB.
通讯机构：
[Zhang, L ] C;Cent South Univ Forestry & Technol, Key Lab Cultivat & Protect Nonwood Forest Trees, Minist Educ, Changsha 410004, Hunan, Peoples R China.
关键词：
Mu oil tree;Flower development;Sexual dimorphism;Sex bias;Ethylene
摘要：
The mu oil tree (Vernicia montana Lour.) is a dioecious species, but the genetic mechanisms underlying its phenotypic sexual dimorphism are unclear. In this study, we determined two pivotal phases of sex differentiation of mu oil tree via morphological and histological analyses of unisexual flowers: (I) differentiation of male or female primordia to produce staminate flowers (SFs) or transient hermaphrodite flowers (HFs), and (II) complete abortion of stamens in transient HFs to generate pistillate flowers (PFs). A total of 1621 sex-biased genes were identified by comparative transcriptome analysis which exhibited elevated rates of protein evolution than unbiased genes. The female-biased genes were enriched in the production of defense compounds while male-biased genes were focused on the production of viable pollens. Transcriptome-based analysis revealed that the differentially expressed genes (DEGs) between PFs and SFs in phase I involved in abscisic acid (ABA), auxin (AUX), cytokinin (CK), ethylene (ET), and gibberellin (GA) biosynthesis and signaling showed higher expression levels in males than in females in general, whereas the DEGs involved in jasmonic acid (JA) and salicylic acid (SA) pathways displayed opposite expression patterns. Moreover, differentially expressed endogenous ABA, AUX, GAs, JA, and SA exhibited consistent biased expression patterns with the DEGs by UPLC-MS-based analysis. Exogenous application of an anti-ethylene plant growth regulator could promote the development of stamens in PFs and generated HFs. Comparative transcriptomic and hormonal analyses of PFs and SFs in phase II indicated an increase in ET concentration when abortion of stamens in PFs occurred. This study suggested that phytohormones play key roles in sex dimorphism and ET may determine the development of stamens in PFs of mu oil tree, which provides an insight into plant sex differentiation mechanisms.
摘要：
Whitfordiodendron filipes var. tomentosum is an endemic plant in China. There have been no chemical or pharmacological studies of this plant reported before. In the current research, eight triterpenes and two steroids were obtained. Their structures were established by the analysis of NMR data and comparison with those reported in the literature. These ten structurally diverse compounds comprised five distinct carbon frameworks with different functionalities. The chemotaxonomic significance of these secondary metabolites was discussed, disclosing the common components between the variant W. filipes var. tomentosum and the species W. filipe. Evaluation of α-glucosidase inhibitory activities of these isolates disclosed that compounds 1, 2, 4, and 6 exhibited significant α-glucosidase inhibitory activities (IC(50) = 16.6-19.2 μM), which were close in value to the positive control acarbose (IC(50) = 11.5 μM). Moreover, the binding modes between the biologically active compounds 1, 2, 4, and 6 and the α-glucosidase protein were preliminarily studied using molecular docking. This study not only showed the chemical and biological profile of the plant W. filipes var. tomentosum but also revealed that these components could be developed as hypoglycemic lead compounds.
作者机构：
[Peng, Jiqing; Peng, JQ; Xue, Chao; Gao, Yu; Cao, Shoujin; Zhang, Yaoyi; Wen, Yuxing; Chen, Tingfeng; Sheng, Song] Cent South Univ Forestry & Technol, Coll Forestry, 498 South Shaoshan Rd, Changsha 410004, Peoples R China.;[Peng, Jiqing; Peng, JQ; Sheng, Song] Hunan Agr Univ, Yuelushan Lab, Qiushi Bldg, Changsha 410128, Peoples R China.;[Peng, Jiqing; Peng, JQ; Sheng, Song] Belt & Rd Int Union Res Ctr Trop Arid Nonwood Fore, 498 South Shaoshan Rd, Changsha 410004, Peoples R China.
通讯机构：
[Peng, JQ; Cao, SJ ] C;[Peng, JQ ] H;Cent South Univ Forestry & Technol, Coll Forestry, 498 South Shaoshan Rd, Changsha 410004, Peoples R China.;Hunan Agr Univ, Yuelushan Lab, Qiushi Bldg, Changsha 410128, Peoples R China.;Belt & Rd Int Union Res Ctr Trop Arid Nonwood Fore, 498 South Shaoshan Rd, Changsha 410004, Peoples R China.
关键词：
hormone;regulation of flowering;transcriptome;molecular mechanism
摘要：
Understanding the molecular mechanisms that regulate flower growth, development, and opening is of paramount importance, yet these processes remain less explored at the genetic level. Flower development in Hydrangea paniculata 'Vanilla Strawberry' is finely tuned through hormonal signals, yet the genetic underpinnings are not well defined. This study addresses the gap by examining the influence of gibberellic acid (GA3), salicylic acid (SA), and ethylene (ETH) on the flowering traits and underlying molecular responses. Treatment with 100 mg/L SA significantly improved chlorophyll content and bolstered the accumulation of soluble sugars and proteins, advancing the flowering onset by 6 days and lengthening the flowering period by 11 days. Concurrently, this treatment enhanced inflorescence dimensions, increasing length, width, and petal area by 22.76%, 26.74%, and 27.45%, respectively. Contrastingly, 100 mg/L GA3 expanded inflorescence size but postponed flowering initiation and decreased inflorescence count. Higher concentrations of SA and GA3, as well as any concentration of ETH, resulted in delayed flowering and inferior inflorescence attributes. A physiological analysis over 50 days revealed that these regulators variably affected sugar and protein levels and modified antioxidant enzyme activities. An RNA-seq analysis during floral development highlighted significant transcriptomic reprogramming, with SA treatment downregulating Myb transcription factors, implicating them in the modulation of flowering timing and stress adaptation. These findings illuminate the complex interplay between hormonal treatments, gene expression, and flowering phenotypes in Hydrangea paniculata, offering valuable perspectives for ornamental horticulture optimization.
作者：
Li Ji;Song Sheng;Fangyuan Shen;Lili Yang;Shizhi Wen;...
期刊：
CATENA,2024年237:107816 ISSN：0341-8162
通讯作者：
Li Ji<&wdkj&>Xu Wang<&wdkj&>Lixue Yang
作者机构：
[Song Sheng; Lili Yang; Shizhi Wen; Gongxiu He] School of Forestry, Central South University of Forestry and Technology, 410004 Changsha, PR China;[Fangyuan Shen; Lixue Yang] Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, 150040 Harbin, PR China;Hunan Key Laboratory for Conservation and Utilization of Biological Resources in the Nanyue Mountainous Region, Hengyang Normal University, 421008 Hengyang, PR China;School of Life Science, Hengyang Normal University, 421008 Hengyang, PR China;[Xu Wang] Research Institute of Tropical Forestry, Chinese Academy of Forestry, 510520 Guangzhou, PR China
通讯机构：
[Li Ji] S;[Xu Wang] R;[Lixue Yang] K;Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, 150040 Harbin, PR China<&wdkj&>Research Institute of Tropical Forestry, Chinese Academy of Forestry, 510520 Guangzhou, PR China<&wdkj&>School of Forestry, Central South University of Forestry and Technology, 410004 Changsha, PR China<&wdkj&>Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, 150040 Harbin, PR China
摘要：
Soil bacteria, as integral components of the soil microbial community, play pivotal roles in biogeochemical cycles and ecosystem functions in boreal forests. The altitudinal patterns of soil bacteria have been widely reported, but their community assembly is uncertain. Here, we investigated the soil bacterial community attributes (diversity, taxonomic and functional composition, and bacterial interactions) and ecological processes associated with community assembly on Mt. Oakley in the northern Greater Khingan Mountains via Illumina MiSeq sequencing and functional annotation tools. The alpha diversity indices of the soil bacteria exhibited a progressively decreasing trend with increasing altitude across seasons. The relative abundance of the dominant bacterial taxa was more sensitive to altitude than to season. More complex (more nodes and links) bacterial interactions were detected at the lowest and highest altitudinal sites, as well as in September. The variations in the taxonomic and functional compositions of the soil bacteria induced by altitude were mainly driven by the variations in soil pH and extracellular enzyme activities. Stochastic (dispersal limitation and drift) processes largely controlled the soil bacterial community assemblages across spatiotemporal scales. The community assemblages of soil bacteria were affected by altitude-induced changes in the taxonomic composition and functional groups. Collectively, our results have significant implications for understanding bacterial biogeography and community assembly mechanisms along altitudinal gradients in boreal forest ecosystems.
摘要：
The distribution of species is mostly influenced by climate synergistic effects and land use. The prediction of endangered species is dependent on fine-scale environmental features, especially in forests. The capture of fine-scale suitable habitats is bounded by low spatial resolution and coarse categorization. In this study, we improved the land use information and forest spatial detail through high forest thematic resolution land use data. To understand the relative influence of environmental factors, suitable habitat models for Chinese endangered tree species (Firmiana danxiaensis) under three climate and high forest thematic resolution land use conditions was constructed. We also assess F. danxiaensis 's response to climate and land use, and differential performance in land use on the suitable habitat. The area of suitable habitat for F. danxiaensis grows slowly under the SSP1-2.6 (shared social pathway scenario) scenario, decreases by 21.33% from the present to 2090 under the SSP2-4.5 scenario, and expands significantly under the SSP5-8.5 scenario. We conclude that high forest thematic resolution land use is beneficial in capturing species' requirements for specific habitats and especially necessary in predicting endangered species. At the same time, the distribution of suitable habitats for species is primarily driven by climate, and limited their development by land use. The study shows that the synthetic effects of climate and land use change on F. danxiaensis are positive, with a marked trend toward the northeast. As a consequence, some endangered species are able to benefit from future SSPs scenarios, in particular they respond more strongly to the SSP5-8.5 scenario than to the other scenarios. Assessing the role of changes in the climate and high forest thematic resolution land use on F. danxiaensis will help promote sustainable land use management and contribute to the conservation policy for Chinese endangered species.
摘要：
In eukaryotic cells, epigenetic modifications of DNA and histone play an important role in the regulation of gene expression. ROXY19 is a member of the plant specific CC-type glutaredoxins (GRXs). We found previously that ROXY19, by association with the TOPLESS/TOPLESS-related (TPL/TPR) family, strongly repressed a subset of genes which were positively regulated by the class II TGA factors. Arabidopsis plants ectopic expressing ROXY19 (ROXY19OE) were hypersensitive to xenobiotic chemicals due to the silencing of detoxification pathway genes. Here, we confirmed in vivo the interaction between ROXY19 and TPL. In order to understand the molecular mechanism underlying ROXY19-TPL module mediated gene repression, DNA methylation and histone deacetylation inhibitors were applied to assess the involvement of epigenetic modifications in the silencing of detoxification pathway genes in ROXY19OE plants. Promoter regions of some ROXY19 repressed genes were not methylated in wild-type/Col-0, and the methylation status were not altered in ROXY19OE. Furthermore, we investigated the role of epigenetic modifications in the antagonistic interplay between ethylene/jasmonic acid (ET/JA) and salicylic acid (SA) signaling pathways, which were supposed to be regulated by ROXY19.
期刊：
European Journal of Forest Research,2024年:1-15 ISSN：1612-4669
通讯作者：
Wu, Lichao;Lu, S;Wang, BP
作者机构：
[Wu, Lichao; Lu, Sheng; Liu, Sen; Fu, YuJia; Li, Xia] Cent South Univ Forestry & Technol, Key Lab Cultivat & Protect Nonwood Forest Trees, Minist Educ, Forestry Coll, Changsha 410004, Hunan, Peoples R China.;[Li, Peng] Guangxi Zhuang Autonomous Reg Forestry Res Inst, Nanning 530002, Guangxi, Peoples R China.;[Wang, Baoping; Qiao, Jie] Chinese Acad Forestry, Res Inst Nontimber Forestry, Zhengzhou 450003, Henan, Peoples R China.;[Li, Hui] Guangxi Diyuanzhiben Fertilizer Ind Co Ltd, Nanning 530022, Guangxi, Peoples R China.
通讯机构：
[Wu, LC; Wang, BP ; Lu, S ] C;Cent South Univ Forestry & Technol, Key Lab Cultivat & Protect Nonwood Forest Trees, Minist Educ, Forestry Coll, Changsha 410004, Hunan, Peoples R China.;Chinese Acad Forestry, Res Inst Nontimber Forestry, Zhengzhou 450003, Henan, Peoples R China.
关键词：
Soil bacteria;Fertilizer application duration;Ecological network;Carbon and nitrogen cycles;Functional genes
摘要：
Paulownia fortunei, one of the world's fastest growing timber tree species, is universally applied with fertilizer as a management approach to meet the nutrient requirements for efficient cultivation. The substantial effects of fertilizer on soil microorganisms in Paulownia plantations have been empirically tested; however, the successive chronosequence of soil microbial carbon and nitrogen functional genes under different fertilizer application durations remains limited. The objective of this study was to explore the characteristics of soil microorganisms involved in carbon and nitrogen cycling and greenhouse gas (GHG) production under different fertilizer application durations. Different fertilizer treatments, i.e., the short-term group (SG) versus the long-term group (LG), and durations were applied to subtropical plantations in southern China and compared with zonal evergreen broad-leaved forests. Results showed that fertilizer treatment significantly increased the relative abundance of Acidobacteriota and the expression of nirK and nosZ. The functional groups that dominated metabolism in SG and LG treatments belonged to Actinobacteria and Acidobacteriota, respectively, suggesting that the nutrient preference of microorganisms in forest soil may change from copiotrophs to oligotrophs with increasing fertilizer application duration. Correlation network analysis showed that the communities that dominated the carbon and nitrogen cycles belonged to Actinobacteria and Acidobacteriota, respectively, and were closely related to ammonium nitrogen and available iron. Actinobacteria and Acidobacteriota were likely the major taxa that affected soil GHG production under different fertilizer application durations. We concluded that long-term fertilizer use changed the preference of microbial nutrient uptake into recalcitrant nutrients, and the sensitivity of the microbial community to nutrients gradually decreased with increasing fertilizer application time. The dominant Actinobacteria affected soil carbon and nitrogen cycles largely by stimulating denitrification to increase the release of nitrous oxide, which might lead to the loss of nitrogen components and the intensification of the GHG effect with increasing fertilizer application time.
作者机构：
[Yang, Zeng; Luan, Liu; Xiudan, Wang] Laboratory of Insect Behavior and Evolutionary Ecology, College of Life Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China Central South University of Forestry and Technology Changsha China
摘要：
A new species of gall inquiline, Synergusdilatatussp. nov., is described from Hubei Province, China. Morphological descriptions, photographs and biological information are provided. Mitochondrial cytochrome oxidase (COI) sequences of the new species were newly obtained and a molecular species delimitation analysis of 12 species of Synergus performed using the ASAP method recovered 16 molecular operational taxonomic units, providing support for recognition of the new species. The results also highlight a few conflicts between morphological and molecular species delimitations in Synergus.
摘要：
Exposure to organic ultraviolet (UV) filters has raised concerns due to their potential adverse effects on environments. However, their toxic mechanisms on plants remain elusive. In this study, using integrative physiological and transcriptomic approaches we investigated the physiological and molecular responses to three representative UV filters, namely oxybenzone (OBZ), avobenzone (AVB), and octinoxate (OMC), in an agricultural model plant tobacco. The exposure to UV filters disrupts the functionality of photosystem reaction centers and the light-harvesting apparatus. Concurrently, UV filters exert a suppressive effect on the expression of genes encoding Rubisco and Calvin-Benson cycle enzymes, resulting in a decreased efficiency of the Calvin-Benson cycle and consequently hampering the process of photosynthesis. Exposure to UV filters leads to significant generation of reactive oxygen species within tobacco leaves and downregulation of oxidoreductase activities. Moreover, UV filters promote abscisic acid (ABA) accumulation by inducing the expression of ABA biosynthesis genes whereas repress indole-3-acetic acid (IAA) biosynthesis gene expression, which induce leaf yellowing and slow plant growth. In summary, the organic UV filters exert toxic effects on tobacco growth by inhibiting chlorophyll synthesis, photosynthesis, and the Calvin-Benson cycle, while generating excessive reactive oxygen species. This study sheds light on the toxic and tolerance mechanisms of UV filters in agricultural crops.
通讯机构：
[Li, H ] C;Cent South Univ Forestry & Technol, Coll Forestry, Changsha, Peoples R China.;Key Lab Natl Forestry Grassland Adm Control Artifi, Changsha, Peoples R China.;Hunan Prov Key Lab Control Forest Dis & Pests, Changsha, Peoples R China.;Minist Educ, Key Lab Nonwood Forest Cultivat & Conservat, Changsha, Peoples R China.
关键词：
Colletotrichum fructicola;carbendazim;mechanism of resistance;β-tubulin isotypes
摘要：
Colletotrichum fructicola is the major pathogen of anthracnose in tea-oil trees in China. Control of anthracnose in tea-oil trees mainly depends on the application of chemical fungicides such as carbendazim. However, the current sensitivity of C. fructicola isolates in tea-oil trees to carbendazim has not been reported. Here, we tested the sensitivity of 121 C. fructicola isolates collected from Guangdong, Guangxi, Guizhou, Hainan, Hunan, Jiangsu, and Jiangxi provinces in China to carbendazim. One hundred and ten isolates were sensitive to carbendazim, and 11 isolates were highly resistant to carbendazim. The growth rates, morphology, and pathogenicity of three resistant isolates were identical to those of three sensitive isolates, which indicates that these resistant isolates could form a resistant population under carbendazim application. These results suggest that carbendazim should not be the sole fungicide in control of anthracnose in tea-oil trees; other fungicides with different mechanisms of action or mixtures of fungicides could be considered. In addition, bioinformatics analysis identified two beta-tubulin isotypes in C. fructicola: Cf beta(1)tub and Cf beta(2)tub. E198A mutation was discovered in the Cf beta(2)tub of three carbendazim-resistant isolates. We also investigated the functional roles of two beta-tubulin isotypes. Cf Delta beta(1)tub exhibited slightly increased sensitivity to carbendazim and normal phenotypes. Surprisingly, Cf Delta beta(2)tub was highly resistant to carbendazim and showed a seriously decreased growth rate, conidial production, pathogenicity, and abnormal hyphae morphology. Promoter replacement mutant Cf Delta beta(2)-2x beta(1) showed partly restored phenotypes, but it was still highly resistant to carbendazim, which suggests that Cf beta(1)tub and Cf beta 2tub are functionally interchangeable to a certain degree.
