Cloning And Preliminary Functional Analysis Of TaIPA1 Gene Regulating Plant Architecture In Wheat(Triticum Aestivum)

Wheat is one of the most important food crops in the world, therefore, improvement of wheat production has great significance on guaranteeing the world’s food security. Wheats with ideal plant architecture displayed robust root system, erect leaves, thick and sturdy stems, moderate tiller numbers and more grains per panicle, which have high potential product. However, it has few reported on molecular mechanism of ideal plant architecture in wheat. Therefore, it has an important significance on cultivating more high-yielding wheat varieties that carrying out the molecular biology research of wheat ideal plant architecture and elucidating its molecular regulation mechanisms.In this study, we cloned the wheat plant architecture related gene TaIPA1, homologousgene of rice OsIPA1/OsSPL14, from the wheat varieties "XIAO YAN 22", and analysised its functions preliminarily. The main results have been summarized as follows:1. We cloned a 1,182 bp length gene TaIPA1 that is homologous with rice ideal plant gene IPA1 in wheat. Bioinformatics analysis showed that the gene TaIPA1,with a 1,158 bp length open reading frame, encoded a protein contained 385 amino acids. The predicted pI of TaIPA1 was 9.12 and molecular weight was 40.25 kD. The results of Protein sequence alignment in different plants showed that TaIPA1 encoded a TaSPL17 protein which contains a conservative SBP- Box structure domain and had miR156 target sites. Phylogenetic analysis indicated that TaIPA1 have closest relationship with aegilops tauschii SPL17 and OsIPA1 / OsSPL14.3. The results of semi-quantitative RT-PCR showed that the gene was expressed in wheat roots, stem bases, leaves and young ears. And the expression level of TaIPA1 in stem bases and young ears were higher than that in roots and leaves. The results indicated that TaIPA1 was important for development of tillers and ears in wheat.4. The results of semi-quantitative RT-PCR in different wheat varieties(lines) showed that the expression level of gene TaIPA1 were correlated positively with plant height or stem diameter. The results indicated that TaIPA1 was important for development of plant height and stems in wheat.5. The gene TaIPA1 was connected with expression vector pGEX6P-1 to construct prokaryotic recombinant expression vector pGEX6P-1- TaIPA1. This recombinant expression vector was transformed into E.coli DH5α, then optimized the temperature, IPTG concentration and time of recombinant plasmid induction expression, showed that the optimal condition for the expression of this fusion protein was 37 ℃, 0.4 mM/L of IPTG for 3h.6. In order to overexpress the TaIPA1 in wheat, the construct pTCK303- TaIPA1 was transformated into wheat by microprojectile bombardment resulted in 161 resistant plants in total. The results of PCR showed that there were 3 positive plants which containing the gene TaIPA1.