Differential Gene Expression Study Of Banana Under Low Nitrogen Stress

Banana?Musa spp.?is an important tropical fruit and is rich in both nutrition and economic benefits.As a kind of fruit,banana is world-famous in fruit markets.Nitrogen is one of the mainly components of protein.Most enzymes are proteins which are the components of cytomembrane,nucleus and cytoplasm.Banana plants are tall and big,requiring a large amount of nitrogen during their growth.Although the traditional application of technologies such as high yielding crop varieties,exhibited irrigation can guarantee the yields,but the nitrogen use efficiency is low.The unused nitrogen fertilizers not only caused a huge wastage in resource but also pollute the environment and soil.How to improve the nitrogen use efficiency and reduce nitrogen input are serious theory and practice problems.In order to research the molecular mechanisms of banana under low nitrogen stress and select the genes associate with it,we cultivated banana seedlings in low nitrogen environment and measured some indices.We also used the technology of RNA-Seq to find differently expressed genes of banana under low nitrogen stress and did some function investigation.The main results are as follows:1.Planted banana seedlings in sand and watered with nutrient solution.Recorded the stem length and leaves yellowing degree and evaluated the impacts of nitrogen to banana growth.We also contrasted wet weight,dry weight and nitrogen contents between two nitrogen levels and made some correlation analysis.The indices were significantly different between control group and low nitrogen stress group.2.Though RNA-Seq,we totally got 12121980,12127542,12121219,12111330 clean reads corresponded to the four samples:the overground part of control group CL;the underground part of control group CR;the overground part of low N stress group NL;the underground part of low nitrogen stress group NR.Compared CL-VS-NL,CR-VS-NR,we obtained 29380 and 31169 differently expressed genes.Then filtered with PPEE<0.05,we finally selected 2066 and 1190 significantly expressed genes.Through GO and Pathway analysis,we found they respectively took part in 44 and 36 biological functions,114 and 106 metabolic pathways.3.We random chose 20 differently expressed genes to validate their expression levels by quantitative real-time PCR?qRT-PCR?,and the results of 16 genes were consistent with RNA-Seq.4.We selected two genes from the significantly differently expressed genes.One is MaNRT2?GSMUA_Achr8T14230₀01?and one is MaWRKY2?Ma01_g18830?.We cloned the two genes' cDNA sequences and predicted its physical and chemical properties of amino acids and functional domains and so on.5.We structed recombinants pCAMBIA 99-1-MaNRT2-3-HA and pCAMBIA 99-1-MaWRKY2-3-HA and made them over expressed in Arabidopsis through agrobacterium to explore its function in low nitrogen stress.The transgenic positive bacterial colonlies were identified by relative antibotics.