Detection Of LRK10 RNAi Accessions And The Relationship Between The Variant Of Copies Number And Wheat Powdery Mildew Fungus Of Triticum Urartu

Receptor-like kinases (RLKs), a family of ubiquitous membrane proteins in higher plants, play important roles in plant growth and development and their responses to environmental stimuli. LRK10-like protein kinase genes were initially found in wheat and related species. It is now well known that these genes exist as multigene family in grass species. Among the 46 subfamilies of plant RLKs recognized to date, the LRK10 type RLKs from grass species have not been well studied. Hence, the main objectives of this research were to investigate the potential functions of LRK10 type RLKs in Triticum urartu and the hexaploid wheat variety Longchun 23.The biological function of LRK10 in hexaploid wheat Longchun 23 was investigated by suppressing LRK10 expression with RNAi. Through comparing the growth and development of wild type plants, the plants with reduced LRK10 expression level, and the transgenic null segregants, it was found that silencing LRK10 expression led to serious delays in heading date in hexaploid wheat. Using fragment analysis, the variation of RLK10 gene fragments was surveyed in 96 Triticum urartu accessions. Concomitantly, the responses of these accessions to a Chinese race of wheat powdery mildew fungus (Blumeria graminis f. sp. tritici) were determined. By comparing the variations of LRK10 gene copy number and mildew resistance response among Triticum urartu accessions, a unique LRK10 gene copy (tentatively designated as TuLRK10-486) was found to associate with strong resistance to mildew disease. Comparing to previously reported LRK10 kinases, the transmembrane and juxtamembrane domains of TuLRK 10-486 carried three unique amino acid substitutions. Thus, our work provides new information on copy number variation of LRK10 genes in Triticum urartu, and reveals an important LRK10 gene member that may be useful for further functional and application studies of LRK10 kinases in wheat and related species.In summary, this study has improved our understanding on the molecular properties of RLKIO genes, and provided evidence for the involvement of RLKIO (and possibly its homologs) in controlling the developmental and physiological characteristics of hexaploid wheat.