Identification Of Soybean MiR159 Family And Functional Analysis Of MiR159e

MicroRNA(miRNA)regulates plant growth and development and responses to biotic and abiotic stresses,including adaptive responses to various nutrient stresses.miR159 is a kind of conservative miRNA.MiR159 has been found to regulate leaf and flower development in Arabidopsis.But the roles of miR159 in soybean are still unclear.In this study,the family of miR159 was identified and target gene of them were predicted,we then explored responses of miR159 to phosphorus(P)nutrient,ABA and NaCl,as well as functions of GmMIR159 e in regulating P homeostasis via using Yuechun 03-3(YC03-3)and overexpressing GmMIR159 e lines.The main results were as follows:(1)Soybean genome contains,six miR159 family members in soybean genome,namely,MIR159 a,MIR159b,MIR159 c,MIR159d,MIR159 e and MIR159 f.MIR159a and MIR159 d are located on soybean chromosome 9;MIR159b and MIR159 e are located on soybean chromosome 7;MIR159c and MIR159 f are located on soybean chromosome 16.The phylogenetic analysis revealed that the miR159 family of soybean is divided into two subgroups.(2)The target genes of six soybean miR159 were predicted with PsRNATarget(http://psrna target.org).The target gene of GmMYB33(Glyma13g25716)encodes nuclear protein,and its N-terminal and full-length of GmMYB33 have transcription activity.(3)MIR159a and MIR159 e was induced in leaves,MIR159 b and MIR159 c was induced in roots,MIR159 f was induced in leaves and roots under long-term low phosphorus(LP)stress.Short-term LP stress inhibited the levels of MIR159 c in leaves and roots,and MIR159 e in roots.Long-term LP stress induced the levels of MIR159 a,MIR159b,MIR159 c and MIR159 f,but inhibited MIR159 d and MIR159 e in flowers.Long-term LP inhibits the abundance of MIR159 a,MIR159c and MIR159 d,but induced that of MIR159 b in nodules.(4)Application of ABA induced the transcript of MIR159 a in leaves and induced that ofMIR159 b in both leaves and roots.MIR159 c was induced in leaves and inhibited in roots,MIR159 d was inhibited in leaves and induced in roots,MIR159 e was inhibited in leaves and roots,in addition,MIR159 f was inhibited in leaves and induced in roots by ABA.(5)NaCl treatment increased the levels of MIR159 a,MIR159b,MIR159 c,and MIR159 e in leaves and roots,respectively,MIR159 d and MIR159 f were induced in roots,but MIR159 f was inhibited in leaves.(6)Activity of soybean MIR159 e promoter was detected in leaf vein,floral organ and seed coat under high P(control)conditions.However,the activity of MIR159 e in anther,radicle and seed coat were strong under LP conditions.The MIR159 e promoter was mainly active in the mature region and root tip of primary root,and meristematic zone of lateral roots in LP.(7)Overexpression of MIR159 e had no effect on the growth and development of soybean and P nutrition in HPHN and LPHN.But in HPLN,overexpression of MIR159 e resulted in the decrease of total P contents in roots and leaves,and the concentration of soluble P in old leaves and nodules.In conclusion,MIR159 gene family of soybean plays a role in response to P signal,ABA and NaCl stress,and miR159 e plays roles in regulating P absorption and reuse in soybean.