果树学报2025，Vol.42Issue(10)：2273-2286,14.DOI:10.13925/j.cnki.gsxb.20250229
甜瓜WAK/WAKL基因家族鉴定及响应疫霉菌侵染的表达分析
Identification of the WAK/WAKL gene family in melon and expression analysis in response to Phytophthora capsici infection
摘要
Abstract
[Objective]As a crucial class of receptor-like protein kinases,genes in the WAK/WAKL fami-ly play a vital role in plant growth and development,disease resistance,and stress responses.The aim of this study was to identify the MeWAK/WAKL family in melon,analyze their expression patterns in re-sistant and susceptible materials under Phytophthora capsici infection,and explore the relationship be-tween this gene family and melon's resistance to Phytophthora blight.[Methods]The melon ZQK9 and E31 are high-resistant and high-susceptible resources to P.capsici,respectively,and they were identi-fied through disease resistance screening in our laboratory.These materials were used to analyze gene expression patterns after inoculation with P.capsici.The pathogen was isolated from diseased melon plants collected in Sanya,Hainan,China.The melon genome data were referenced from Melon(DHL92)v4.0.Based on the conserved domain features,the melon WAK/WAKL family members were identified through genome-wide screening.Subsequent analyses including gene structure,protein physi-cochemical properties,chromosome distribution,subcellular localization prediction,promoter cis-act-ing elements,and phylogenetic relationships were conducted by a serious of softwares and visualized using TBtools software.Quantitative real-time PCR(qRT-PCR)was employed to investigate the expres-sion patterns of family members in resistant(ZQK9)and susceptible(E31)samples at 2,24 and 72 hours post-inoculation(hpi)with P.capsici,aiming to elucidate their correlation with disease resistance in melon.[Results]The WAK/WAKL family in melon comprised 20 genes,including 4 WAK genes and 16 WAKL genes,which were distributed across 9 melon chromosomes.Among them,7 genes were clus-tered on chromosome 3,suggesting that these genes might function through coordinated expression.The results of subcellular localization prediction indicated that the WAK/WAKL family genes in melon were mainly localized in the extracellular or plasma membrane,consistent with reports in other crops.The phylogenetic tree divided 113 WAK/WAKL family genes from melon and model plants such as Nico-tiana benthamiana,Arabidopsis thaliana,and Solanum lycopersicum into 6 groups.The MeWAK/WAKL family genes in melon were mainly distributed in group Ⅰ and Ⅵ.Group Ⅰ was independently composed of 7 MeWAKL genes,indicating that the members of the MeWAK/WAKL family in melon might have un-dergone strong natural selection(such as extreme environments)during the evolutionary process,show-ing a phenomenon of rapid evolution.In addition,6 of these 7 genes were clustered on chromosome 3.This clustering might lead to functional redundancy,but it could also reduce the negative impacts caused by structural variations such as chromosome breakage in individuals under strong external pres-sure,thus being retained in evolution.Domain analysis showed that the WAK/WAKL family genes in melon contained 1 to 7 exons.Among the 20 family genes,17 genes contained the GUB-WAK bind(wall-associated receptor kinase galacturonan-binding)domain.Seven genes contained the GUB-WAK bind,EGF(epidermal growth factor),and serine-threonine kinase domains simultaneously.Seven genes only contained the GUB-WAK bind domain,and 2 genes contained both EGF domain and the kinase do-main without GUB-WAK bind domain.Analysis of promoter cis-acting elements revealed that the pro-moters of the WAK/WAKL family genes in melon contained light-responsive elements(LTR),regulatory element related to meristem expression(MEE),response elements for various hormones(MeJA,SA,ABA,Auxin,and GA),as well as elements related to drought-inducibility and defense and stress respon-siveness.This suggested that the WAK/WAKL family genes in melon might play important roles in dis-ease resistance,stress tolerance,and growth and development of melon.Two genes,MeWAKL4 and Me-WAKL16,which were specifically up-regulated after inoculation in resistant melon ZQK9,were screened through qRT-PCR analysis.MeWAKL4 was a transmembrane protein containing the GUB-WAK bind domain,WAK_assoc domain,and kinase domain,might play an important role in recogniz-ing pathogen infection signals and transmitting them into the cell.The MeWAKL 16 protein had only one GUB-WAK bind domain,was localized on the plasma membrane,and had a transmembrane struc-ture.Based on the resistance mechanism of the maize gray leaf spot resistance gene Zm WAKL,we spec-ulated that MeWAKL16 might play a role in recognizing pathogen infection signals and transmitting the signals into the cell by forming a complex with other kinase(s)on the plasma membrane.The detail reg-ulatory mechanism required further experimental research.[Conclusion]In this study,20 MeWAK/WAKL family genes in melon were identified.Through gene domain and promoter cis-acting element analyses,it could be speculated that MeWAKs/WAKLs could respond to various hormone or stress sig-nals and regulate the plant's disease resistance,stress tolerance,and growth and development processes.Two genes,MeWAKL4 and MeWAKL16,were screened via qRT-PCR and showed specific up-regula-tion at 24 and 72 hpi in resistant melon ZQK9,while their expression levels exhibited no significant dif-ferences in susceptible E31.They might be involved in the signal pathway of melon's resistance to Phy-tophthora blight.This study laid a foundation for further research on the specific relationship between melon MeWAK/WAKL family genes and the resistance response to Phytophthora blight.关键词
甜瓜/WAK/WAKL基因家族/疫病/表达分析Key words
Melon/WAK/WAKL family/Phytophthora blight/Expression analysis分类
园艺学与植物营养学引用本文复制引用
张林龙,王方方,何玉敏,薛冰,沈晨阳,李杰,赵胜杰,徐志红,王平勇..甜瓜WAK/WAKL基因家族鉴定及响应疫霉菌侵染的表达分析[J].果树学报,2025,42(10):2273-2286,14.基金项目
中国农业科学院郑州果树研究所协同创新专项(ZGS202307) （ZGS202307）
国家自然科学基金项目(32172573) （32172573）
中国农业科学院科技创新工程(CAAS-ASTIP-ZFRI-06-202501,CAAS-ASTIP-2025-ZFRI,2060299-2-25) （CAAS-ASTIP-ZFRI-06-202501,CAAS-ASTIP-2025-ZFRI,2060299-2-25）
河南省科技攻关项目(242102110289) （242102110289）
三亚中国农业科学院国家南繁研究院南繁专项(YBXM2419) （YBXM2419）
河南省西瓜甜瓜产业技术体系(HARS-22-10-S) （HARS-22-10-S）
