A Disulphide Isomerase Gene(Pdi-V) From Haynaldia Villosa Contributes To Powdery Mildew Resistance In Common Wheat

【摘要】：In this study, we reported the contribution of PDI-like gene from wheat wild relative Haynaldia villosa in combating against powdery mildew(Bgt). PDI-V was identified by Yeast two hybrid as an interacting protein with CMPG1-V, which encodes an E3 ligase and is a positive regulator for powdery mildew resistance. The PDI-V contains two conserved thioredoxin active domains(a and a′) and an inactive domain(b). Our results showed that PDI-V could be mono-ubiquitinated by CMPG1-V without detected degradation. The PDI-V was located on the 5 V chromosome in H. villosa genome and PDI-V is subcellularly localized in endoplasmic reticulum lumen. PDI-V was induced in leaves when challenged with Bgt. Visible Bgt spores could not be detected when silencing the PDIs in PM resistant T. durum-H. villosa amphiploid, but microscopically display increased fungal growth. Single cell transient over-expression of PDI-V decreased the haustorium index of a moderately PM susceptible wheat variety Yangmai-158. Stable transgenic lines over-expressing PDI-V displayed improved PM resistance at both seedling and adult stages. Over-expression of construct only containing the active thioredoxin domain a could also equally reduce the HI as the full length gene, indicating its critical role in defense responses. Over-expressed point mutated PDI-VC57 Ain Yangmai-158 could not improve PM resistance, further confirming the essential role of the conserved TRX-like domain a for proper functioning of PDI-V. Taken together, these evidences indicates that PDI-V plays positive role in PM resistance and represents a potential novel source for wheat improvement.