Clonging And Charaterizatino Of GmCSN5s Functions In Soybean Adaptation To Phosphorus Deficiency

Phosphorus(P)is an essential macronutrient mineral,which plays an important role in plant growth and development.However,phosphate(Pi)availability on soils is often low,and is hard to meet the requirement for plant growth.In order to adapt to low phosphorus stress,plants have developed a series of adaptive mechanisms,such as root morphology and architecture changes,and anthocyanins accumulations in leaves.Soybean(Glycine max)is a very important grain and oil crop.However,soybean production and seed quality is adversely affected by P deficiency.In our pervious study,it was found that Gm CSN5 could interact with a protein phosphatase,Gm HAD1-2 through two yeast hybridization analysis.In the present study,two Gm CSN5 members were identified and characterized in the soybean genome through bioinformatics analysis.Subsequently,their transcription patterns were investigated in soybean under Pi sufficient and deficient conditions.Furthermore,their functions in plants were studied in Arabidopsis thaliana with their overexpression.The main results are follows:1)In soybean genome,there are two Gm CSN5,Gm CSN5-1 and Gm CSN5-2.Their transient expression in tobacco epidermal cells showed that both Gm CSN5-1 and Gm CSN5-2 localized to plasma membranes,nucleus and cytoplasms.2)Phosphorus deficiency inhibited growth of two soybean cultivars,including YC03-3 and BD2.However,root length was increased by Pi starvation at 12 and 15 d of P treatments.Quantitative PCR analysis showed that expression levels of Gm CSN5-1 and Gm CSN5-2 were enhanced in soybean roots at 12 and 15 d of Pi starvation.Furthermore,at 12 d of Pi starvation,transcripts of both genes were increased in roots,young and old leaves in YC03-3,especially in old leaves in which their transcripts were increased by about 2.6 folds.3)Two transgenic lines were separately obtained in Arabidopsis with Gm CSN5-1 or Gm CSN5-2 overexpression.In solid MS medium,low P stress inhibited tap root growth.However,overexpression of Gm CSN5-1 or Gm CSN5-2 led to longer tap root length than wild type at two P levels.Furthermore,biomass of all transgenic lines with Gm CSN5-1 or Gm CSN5-2 overexpression was higher than wild type under P deficient conditions,suggesting that Gm CSN5-1 and Gm CSN5-2 might participate in regulating root growth at low P level.4)Plant growth and an anthocyanin accumulation in Arabidopsis were further investigated at two P levels under soil culture conditions.It was found that low Pi availability inhibited Arabidopsis growth,but enhanced anthocyanin accumulation in leaves.Furthermore,overexpression of Gm CSN5-1 or Gm CSN5-2 led to increased accumulations of anthocyanin in leaves under low Pi conditions,strongly suggesting that Gm CSN5-1 and Gm CSN5-2 might play a role in anthocyanin synthesis in plants.Taken together,spatial expression patterns of Gm CSN5-1 and Gm CSN5-2 were elucidated in soybean responsive to Pi starvation.Our results suggested that Gm CSN5-1 and Gm CSN5-2 might participate in root growth and anthocyanin synthesis in plants responsive to Pi starvation.All the results might provide candidate gene and clue to further understanding of biological mechanisms underlying soybean responsive to pi starvation,and thus contribute to development of crop cultivars with high P efficiency in future.