Research Of LecRK-?.2-Mediated Involved In Hypocotyl Growth And Flowering Time In Arabidopsis

As a class of important receptor-like kinases,Lect in receptor-like kinases(LecRKs)regulate several physio logical processes in plants such as plant growth,development,immunit y and hormone regulat ion.LecRKs have been widely concerned because of their significant funct ion in plant disease and pest resistance,but they are rarely reported about the funct ion of growth and development.This study explored the funct ion of LecRK-?.2 gene of the Arabidopsis thaliana L-t ype LecRKs gene family as the research object.The results of bio informatical analysis of protein mo lecular structure illustrated that LecRK-?.2 belongs to t ypical receptor-like kinase protein,with receptor domain,transmembrane domain and kinase domain.Genet ic analysis shows that there are two members of the eighth subfamily of LecRKs,LecRK-?.1 and LecRK-?.2.From the tissue expression pattern of LecRK-?.2,we found that the relat ive expressio n levels of LecRK-?.2 gene is highest during period of seed development,indicat ing that LecRK-?.2 gene may be involved in seed development;according to GO analysis of sugar-related genes,the mo lecular function result shows that the funct ion of sugar-related genes has a vital correlat ion with LecRKs family,implying that this family may be involved in sugar signaling mo lecules.We obtain funct ional delet ion mutants by the Triplet repeat-primed to ident ify the homozygous delet ion mutants and gain overexpressio n mutant lines through Transformat ion Protocol.By observing the growth and development phenot ype of Arabidopsis seedlings under different sugar treat ments,we found that LecRK-?.2 gene negat ively regulates the seed germinat ion rate and root growth of Arabidopsis,which indicated that LecRK-?.2 gene is involved in regulat ing Arabidopsis seed germinat ion and root growth.By observing the phenot ype of hypocotyl length of Arabidopsis wild type Col-0,LecRK-?.2 deletion mutants and over-expressed mutants,it was found that the hypocot yl length of over-expressed plant was shorter than wild t ype under the treat by Glc and BR.The effect of glucose on the hypocot yls of BAK1 loss-of-funct ion mutants and overexpressing mutant lines is the same as BR,indicating that LecRK-?.2 is likely to be involved in the growth regulation of Arabidopsis hypocot yls by Glc and BR.Real-time fluorescence quantitative PCR analysis of the expression level of sugar transporter signals,BR signaling and auxin-related genes in response to exogenous sugar and BR suggested the effect of LecRK-?.2 gene on hypocotyl growth was involved in the complex sugar and hormone cross-talk signaling pathway.Stat ist ics of the flowering t ime of Arabidopsis wild-t ype Col-0,LecRK-?.2 delet ion mutant and over-expressed mutant plants show that flowering t ime of overexpressio n plants are later than wild type and the number of rosette leaves is more than that of wild t ype,which indicates that the genes of L-type LecRKs ? family may play a role in regulat ing the flowering time of Arabidopsis.Researching on the funct ion of LecRK-?.2 gene provides references for analyzing the physio logical funct ion of other members of LecRKs gene family.