| With the increasing demand of maize（Zea mays L.）in food,feedstocks and industrial products and the decrease of agricultural land,increasing planting density has been an effective means of increasing maize yield per unit of land area.Plant use several classes of photoreceptors to monitior the change of in the ratio of red to far-red light,which could trigger the shade avoidance syndrome and reduce yield.Previous studies have shown that the red and far-red photoreceptors phytochromes are responsible for triggering the shade avoidance in Arabidopsis.However,there are few studies on PHYC in maize.The functions of maize PHYA and PHYB in light signaling and photomorphogenesis have been studied,but PHYC is rarely studied.In order to study the function of Zm PHYC1 and Zm PHYC2 and the effect of their in maize photomorphogenesis and plant height,in this study,we obtained c DNA sequences of Zm PHYC1 and Zm PHYC2 from NCBI website,analyzed the protein domains of maize PHYC and phylogenetic tree of PHYC proteins in common plant species by bioinformatics,and verified the functions of Zm PHYC1 and Zm PHYC2 in Col-0 ecotype,phy C-2 mutant and maize inbred line Zong31 by transgenic technology.Zm PHYC1 and Zm PHYC2 were cloned from maize inbred line B73 by RT-PCR,the length of the encoding region of Zm PHYC1 and Zm PHYC2 was 3405 bp,encoding 1135 amino acid residues,and the molecular weights of the proteins were 126.14 k D and 126.07 k D,respectively.Zm PHYC1 and Zm PHYC2 have similar domains to the PHYC proteins of Arabidopsis thaliana,rice and sorghum.There were 1 PAS2 domains,1 GAF domain,1 PHY domain,2 PAS repeat domains,and1 Histidine kinase A domain Histidine kinase ATPase domain（HATPasec）and a Histidine kinase ATPase domain（HATPasec）.The amino acid sequence homology analysis showed that Zm PHYC1 and Zm PHYC2 had the highest homology with sorghum PHYC.The exogenous expression of Zm PHYC1 and Zm PHYC2 in Arabidopsis thaliana not only complements the long hypocotyl phenotype caused by phy C-2 mutant,but also promotes the de-etiolation reaction of seedlings under continuous red and blue light conditions and inhives the long-term growth of seedlings under shade conditions.The effect of Zm PHYC1 was better than that of Zm PHYC2 in promoting the de-etiolation reaction and inhibiting the shade avoidance reaction.The overexpression of Zm PHYC1 and Zm PHYC2 in maize led to the decrease of plant height and ear position,but the regulation effect of Zm PHYC1 on plant height was more significant than that of Zm PHYC2. |
