Cloning And Functional Analysis Of G-type Lectin Receptor Kinase Gene TaLecRK Of Wheat Cultivar Xiaoyan 6

Wheat stripe rust is a fungal disease caused by Puccinia striiformis f.sp.tritici（Pst）.Pst with the characteristics of strong toxic variability and long-distance transmission is widely spread and endemic in wheat-producing areas all over the world and seriously affects wheat production and threatens food security.Abundant practices have proven that growing wheat resistant cultivars is the most economical,safest and most effective strategy to manage stripe rust.Xiaoyan 6（XY6）is a typical example of wheat cultivars with high-temperature seedling-plant（HTSP）resistance to Pst,which has non-race specific and durable wheat resistance characteristics.Since its promotion in the 1980s,it has maintained resistance to Pst in the field.Lectin receptor kinases（Lec RLKs）play an important role in plant growth and resistance to various pathogens.However,the role of Lec RLKs in wheat HTSP resistance to Pst have not been reported.Based on the transcriptome sequencing data of the interaction among XY6,Pst and temperature,we identified a G-type lectin receptor kinase gene TaLecRK from 1395differentially expressed genes（DEGs）.In this study,we used XY6 and Pst race CYR32 as materials and studied the function of TaLecRK in wheat HTSP resistance to Pst.The main results of this research are as follows:1.The G-type lectin receptor kinase gene TaLecRK was cloned from XY6.TaLecRK is located on the 6D chromosome with 1713 bp,encodes a 443 amino acid protein with an estimated molecular mass of 48.54 k Da and an isoelectric point（PI value）of 6.8.2.The expression pattern of TaLecRK gene in XY6 was clarified.The different temperature did not affect the expression of TaLecRK in uninoculated plants with Pst;TaLecRK gene in wheat was upregulated 5.96 folds under high temperature treatment compared with normal temperature in inoculated plants;TaLecRK gene was highly expressed in wheat leaves,almost not expressed in roots and stems;TaLecRK gene was up-regulated16.93 folds under exogenous hormone ABA treatment.3.TaLecRK positively regulates wheat HTSP to Pst by regulating the production of reactive oxygen specie（ROS）.Transient silencing of TaLecRK reduced HTSP resistance to Pst of XY 6 with decreased on the area of H₂O₂ production at each infection site,increased uredinium density and uredinium length in response to Pst inoculation and high temperature treatment.The ROS signaling pathway defense related gene Ta CAT was up-regulated;the transient overexpression of TaLecRK in Nicotiana benthamiana could induce programmed cell death in leaves.4.TaLecRK is located in the chloroplast and interacts with the Tox A binding protein Tox ABP.A total of four proteins that interact with TaLecRK were screened by the nuclear system yeast double-hybrid mating method.TaLecRK interacts with Tox ABP,which is related to programmed cell death.