棉花脂肪酸转运蛋白GhSTR2基因的克隆与抗病功能分析

Cloning and functional analysis of GhSTR2 gene of cotton fatty acid transporter in disease resistance

脂肪酸转运蛋白(STR)可调控细胞内脂肪酸向外运输,在植物生长发育及响应生物胁迫等方面发挥着重要作用。研究报道蒺藜苜蓿STR基因对菌根真菌的抗病性发挥重要作用。为解析GhSTR基因在棉花应对枯萎病与黄萎病反应中的作用,并为棉花抗病分子育种提供基因资源,本试验根据苜蓿STR2基因序列,在棉花基因组数据库中比对出GhSTR2基因同源序列,并进行基因克隆和生物信息学分析。采用qRTPCR方法检测枯萎病与黄萎病处理后不同时间点棉花中GhSTR2基因的表达模式;利用病毒诱导的基因沉默(VIGS)技术验证GhSTR2基因在棉花枯、黄萎病中的抗病作用。结果表明:克隆的GhSTR2基因开放阅读框为2175 bp,编码724个氨基酸,预测为一种不稳定的跨膜蛋白,含一个ABC_TRANSPORTER结构域;qRT-PCR分析表明,枯萎病菌与黄萎病菌分别胁迫后,GhSTR2基因的相对表达量较对照组具有显著性差异变化;VIGS沉默GhSTR2基因的棉株与阴性对照植株TRV:00相比,沉默植株抗病性显著提高,其病情指数、剖秆检测的维管束褐变程度、侵染茎段效率、真菌菌丝数量等均显著低于对照组。以上结果显示GhSTR2基因参与了棉花对枯、黄萎病的防御过程,是棉花抗病反应的一个负相关因子。

The fatty acid transporter STR can regulate the outward transport of intracellular fatty acids,playing an important role in plant growth,development,and response to biotic stress.The study reported that the STR gene of Tribulus terrestris alfalfa plays an important role in disease resistance of mycorrhizal fungi.To analyze the role of GhsTR gene in cotton response to Fusarium wilt and Verticillium wilt,and to provide genetic resources for cotton molecular breeding for disease resistance.This experiment aligned the homologous sequence of GhsTR2 gene in the cotton genome database based on the sequence of al-falfa STR2 gene,and gene was cloned and the sequence was analyzed.qRT-PCR method was used to de-tect the expression patterns of GhsTR2 gene in cotton at different time points after treatment with Fusari-um wilt and Verticillium wilt,and virus induced gene silencing(ViGs)technology was used to verify the effect of GhsTR2 gene in cotton resistance to Fusarium wilt and Verticillium wilt.The results showed that the cloned GhsTR2 gene,encods 724 amino acids,has an open reading frame of 2175 bp,and was predicted to be an unstable transmembrane protein containing an ABC_TRANSPORTER domain.The real-time qRT-PCR analysis showed that there was a significant difference in the relative expression level of GhSTR2 gene after treatment by pathogenic bacteria of Verticillium wilt and Fusarium wilt respectively compared with the control.Compared with the negative control plant TRV:00,cotton plants with the GhSTR2 gene silenced by ViGS showed a significant improvement in disease resistance.The disease index,degree of vascular bundle browning detected by stem dissection,efficiency of infected stem segments,and number of fungal hyphae in the silenced plants were significantly lower than those in the control group.The above results indicate that the GhsTR2 gene is involved in the defense process of cotton against Fusarium wilt and Verticillium wilt,and is a negative correlation factor in cotton's disease resistance response.