Cloning And Characterization Of PLDδ In Wheat

Wheat(Triticum aestivum L.) is the third largest staple crops in China and closely related to natioanl food security. There are 99 million hm2 saline and alkaline soil in China. Salt stress restricts wheat growth and development, then decreases wheat yield severely sometimes.Therefore, it is very important to clarify the mechanism underlying salt responses and to improve the salt tolerance in wheat. In this study, TaPLDδ gene was cloned from common wheat cultivar Yangmai 158 and characterized using genetic, physiological and molecular approaches. The results shows that TaPLDδ gene involved in flower development and plant responses to salt stress. The main results list as follows.(1) Full-length cDNA sequence(2749bp) were cloned from common wheat, harboring a ORF(2589bp) region for encoding a protein with 862 amino acids. TaPLDδ protein contains highly conserved and typical PLD domains and two HKD motifs.(2) TaPLDδ expresss in all tissues detected with higher expression level in young leaves,young roots. TaPLDδ can be upregulated by osmotic stress, MeJA, ABA, GA and SA.(3) Transgenic plants with Dex(dexamethasone) inducible TaPLDδ are obtained and subjected to salt stress. The results show that the roots of trangenic plants are longer than wild types, and the lateral roots emerge one or two days earlier in salt stress. The enzymatic activity of POD, CAT and SOD and content of MDA in induced transgenic plants is apparently higher than that of wild type, which are consistent with the relevant results by 3,3’-diaminobenzidine staining.(4) Transgenic plants flower early after the overexpression of TaPLDδ is induced by DEX.The quantitative PCR proves the expression of AP1, AP3 and VRN1 increase in transgenic plants, which promote the floral transition and flower establishment.