Isolation And Functional Analysis Of Phytochrome A Genes In Wheat And Maize

Phytochromes are an important class of light receptors which regulate the photomorphogenesis in the process of plant development. The duplication genes of phytochromes exist in the monocot of common wheat (T. aestivum L) and maize (Zea mays L.). We have cloned the phytochrome A subfamily from the common wheat and maize by using RT-PCR. Phylogenetic tree analysis, RNA transcription and protein structure of phytochrome A gene of wheat and maize are studied. In addition, protein functions of maize phytochrome A are confirmed partly. The main conclusions as follows:I Isolation, expression analysis and protein structures of Phytochrome A1,A2 and A3 genes in common wheat1 The genomic sequences of TaPhyA 1, A2 and A3 genes of Chinese Spring wheat (T. aestivum L) were obtained by using RT-PCR. The mRNA coding sequences of TaPhyA 1,2,3 were 3393 bp, but the stop code mutant was detected in the site of the 2669th base of TaPhyA2 sequences. TaPHYA1,3 were composed of a GAF domain, a phytochrome domain, two PAS domains, a his Kinase domain and a histidine kinase-like ATPase domain. But TaPhyA2 was only composed of a GAF domain, a phytochrome domain, two PAS domains.2 Phylogenetic tree analysis indicated that TaPHYA1 was closed to PHYA of B01(AA:T. monnococcum L), that TaPHYA2 was closed to PHYA of PI449340(SS:T. speltoides Grren. ex Richter)and TaPHYA3 was closed to PHYA of Ae45(DD:T. tauschii Schmal).3 The tissue-specific expressions level of TaPhyA1, A2 and A3 genes were variation in different tissue, and the relative expression level of TaPhyA3 was lower in the leaf than in other tissues.4 The relative expressions level of TaPhyAs were respectively higher in continuous darkness, far-red light and in blue ligtht congditions than continuous red light and white light conditions. When the light conditions were changed, the expression level of TaPhyAs can be induced to increase by darkness and far-red light, Which also can be induced to reduce by white and far red light. In addition, The expressions of TaphyA1,3 were very similar to the expression of total TaPhyAs regulated by light conditions. The expression of TaphyA1,3 can be up-regulated from white light to far-red light and dark conditions, but the expression of TaphyA1,3 can be down-regulted from darkness to far-red light and white light.â…¡Primary analysis of protein structures and expression patterns responding to different light treatments of two phytochrome A genes in maize1 Both ZmPHYA1 and ZmPHYA2 were composed of a GAF domain, a phytochrome domain, two PAS domains, a his-Kinase domain and a histidine kinase-like ATPase domain.2 Phylogenetic tree analysis indicated that ZmPHYA2 was more closed to PHYA of Sorghum bicolor than ZmPHYA1 at amino acid lelvel.3 The ZmPHYA1 and ZmPHYA2 physically interacted with each other through the 539-amino acid of their C terminals which were composed of two PAS domains, a his-Kinase domain and a histidine kinase-like ATPase domain. The ZmPHYA1 and ZmPHYA2 physically interacted with the full length of Arabidopsis SPA1 proteins that the NT696 domain was important. The results showed that protein degradation of ZmPHYA1 and ZmPHYA2 may be mediated by SPA1 in maize.4 The expressions levels of both ZmPhyA1 and ZmPhyA2 were regulated by different light. The results showed higher expression lelvels in darkness, far-red and blue light conditions, but lower in red and white light conditions.The hypocotyl lengths of transgenic Arabidopsis lines of ZmPHYA1 and ZmPHYA2 were obviously different in continuous far-red, red, blue and wheak white light conditions.