摘要
禾谷镰孢(Fusarium graminearum,Fg)穗腐病是造成我国西南地区玉米减产的主要因素之一。本研究选取对禾谷镰孢穗腐病表现高抗和高感的玉米自交系各2个(高抗系4019和NMJT,高感系黄早四和GEMS61),对授粉后15 d的籽粒接种禾谷镰孢,设置3个侵染时间点进行取样和转录组测序,通过差异表达基因(differentially expressed genes,DEG)分析并结合前期全基因组关联分析(genome-wide association study,GWAS)共定位、qRT-PCR验证、克隆及其序列比对和表达模式研究,对玉米抗禾谷镰孢穗腐病候选基因进行筛选、克隆和初步验证。主要研究结果如下:(1)转录组分析结果表明,禾谷镰孢侵染3个时间点抗感材料之间均存在大量的DEG;2个抗病材料间存在共同的响应机制,DEG主要富集于植物次生代谢产物、植物激素信号转导、钙信号通路和抗氧化系统等通路;同时,2个抗病材料间也存在特异的响应机制,通过调控各自特异的基因表达增强其抗病性。(2)结合转录组DEG与GWAS共定位到24个基因,根据基因功能注释和文献报道,从中预测了12个可能与禾谷镰孢穗腐病抗性相关的候选基因;经qRT-PCR验证并进行克隆,成功克隆出2个基因Zm00001eb104020和Zm00001eb195780。(3)对2个候选基因进行序列比对和时空表达模式分析表明,2个基因编码的蛋白序列在抗感材料间存在共同的位点突变和缺失;2个候选基因的时空表达特征存在明显差异,但其表达量在抗病材料中均较感病材料高,且均表现为接种禾谷镰孢后在籽粒中被诱导显著上调。研究结果为后续玉米抗禾谷镰孢穗腐病候选基因的分子机制解析、功能验证及抗病种质的选育提供了理论依据。
Gibberella ear rot(GER)of maize(Zea mays L.),caused by Fusarium graminearum(Fg),is a major factor contributing to yield losses in southwestern China.In this study,two highly resistant inbred lines(4019 and NMJT)and two highly susceptible lines(Huangzaosi and GEMS61)were selected.Kernels at 15 days after pollination were inoculated with Fg,and samples were collected at three post-infection time points for transcriptome sequencing.Candidate resistance genes were identified,cloned,and preliminarily validated through a combination of differentially expressed gene(DEG)analysis,previous genome-wide association study(GWAS)results,qRT-PCR validation,cloning and sequence alignment,and expression pattern analysis.The main findings were as follows:(1)Transcriptome analysis revealed a large number of DEGs between resistant and susceptible lines at all three infection stages.The two resistant lines shared common defense responses,with DEGs significantly enriched in pathways such as plant secondary metabolism,plant hormone signal transduction,calcium signaling,and the antioxidant system.In addition,each resistant line exhibited specific defense mechanisms by regulating unique gene expression patterns.(2)Integration of DEG and GWAS data identified 24 co-localized genes.Based on gene annotation and literature reports,12 genes were predicted as potential candidates for GER resistance.Among these,two genes—Zm00001eb104020 and Zm00001eb195780—were successfully cloned and validated by qRT-PCR.(3)Protein sequence analysis revealed shared mutations and deletions between resistant and susceptible lines.The two candidate genes also showed distinct spatiotemporal expression patterns,with significantly higher expression levels in resistant lines.Both genes were strongly induced and upregulated in kernels following Fg inoculation.These results provide a theoretical foundation for further functional characterization of GER resistance mechanisms and the breeding of resistant maize germplasm.
作者
董丽华
董成艳
李正楠
余静
叶靓
刘芳
谭静
Dong Li-Hua;Dong Cheng-Yan;Li Zheng-Nan;Yu Jing;Ye Liang;Liu Fang;Tan Jing(School of Agriculture,Yunnan University,Kunming 650500,Yunnan,China)
出处
《作物学报》
北大核心
2026年第1期131-147,共17页
Acta Agronomica Sinica
基金
国家自然科学基金项目(32260516)资助。
关键词
玉米
禾谷镰孢穗腐病
抗性候选基因
功能位点鉴定
时空表达特征
maize
gibberella ear rot
candidate resistance genes
functional site identification
spatio-temporal expression characteristics
