小麦自噬相关基因ATG10的克隆及白粉菌侵染诱导的ATG10的表达

摘要

细胞自噬是一种保守的真核生物细胞内物质分解和循环利用机制，在植物生长、发育和逆境响应等过程中均扮演了重要角色。自噬相关蛋白ATG10是参与自噬小体形成的关键因子之一。利用同源克隆方法，从经白粉病菌诱导48 h的小麦材料92R137/扬麦1587中克隆了ATG10基因家族3个成员(TaATG10a、TaATG10b和TaATG10c)。序列特征分析、物种间的比较和进化分析，以及酵母功能互补实验结果证实，这3个基因均为酵母 ATG10的功能性同源基因。TaATG10a和TaATG10b的基因组序列具有相似的6外显子-5内含子基因结构。RT-PCR分析还发现这2个基因都具有2种可变剪接产物。TaATG10a和TaATG10b的GFP融合蛋白被定位于洋葱表皮细胞的细胞质中。白粉菌侵染能够诱导TaATG10a和TaATG10b表达，因此推测，小麦针对白粉菌侵染的免疫反应涉及对TaATG10及其参与的自噬过程的调控，其调控模式因小麦抗、感白粉病反应、不同类型抗病基因介导的免疫反应和不同遗传背景下的感病反应而差异明显，说明TaATG10及其参与的自噬过程与小麦-白粉菌互作反应关系的复杂性。从外源激素处理诱导的表达情况还发现，抗、感白粉病的表型差异可能涉及抗、感材料TaATG10基因对同种激素(SA、乙烯或ABA)信号的不同响应模式。%Autophagy, a conserved eukaryotic cellular process functioning in material decomposition and nutrient recycling, is deeply involved in plant growth, development, and response to stress. ATG10 is one of the key factors required in autophagosome formation. In this study, we identified three members (TaATG10a, TaATG10b, and TaATG10c) of the ATG10 family in common wheat 92R137/Yangmai 1587 induced by Blumeria graminis f. sp. tritici (Bgt) for 48 h, using homologous cloning technique. The three TaAGT10s shared high similarity with their counterparts from other model plants. Expression of TaATG10a or TaATG10b rescued the autophagy process in ATG10-defective yeast mutant, suggesting that both genes are functional homologues of yeast ATG10. TaATG10a and TaATG10b had similar gene models containing six exons and five introns, and both had two alternatively spliced mRNA isoforms according to RT-PCR assay. TaATG10a-and TaATG10b-GFP fusion structures were localized in cytosol of onion epidermal cells. The expressions of TaATG10a and TaATG10b were induced by the infection of Bgt, implying that TaATG10s and their involved autophagy process are implicated in the wheat immune response to Bgt. This implication is com-plex because the regulated expression profiles of TaATG10a and TaATG10b are different between resistant and susceptible reac-tions, between different types of resistance gene-mediated immune reactions, and between susceptible reactions on different ge-netic backgrounds. Besides, exogenous phytohormones also modulated the expression of TaATG10a and TaATG10b. Different Bgt immune reactions might result partially from the different response patterns of TaATG10s to salicylic acid, ethylene, or ab-scisic acid signaling pathways between in resistant genotypes and in susceptible genotypes.