| Occurring frequency of natural disaster such as drought presents an increasing trend with global warming.Drought not only affects plant growth,but also induces the decrease of crop yield.In order to ensure the sustained agricultural development in our country,more attention should be paid to coping with drought and improving water usage efficiency of crop.Especially,it has the great theoretical significance and application value for studying deeply the molecular mechanism of plant in responses to drought by using modern molecular biology technology.Long noncoding RNA(lncRNA)plays an important role in the process of plants responding to biological stress and abiotic stress,but its role in plant drought response is still unclear.A novel long noncoding RNA,lincRNA13853 has been identified when we previously screened abscisic acid(ABA)related phenotyping with T-DNA mutants of Arabidopsis thaliana.The lincRNA13853 mutants not only showed the decrease of ABA sensitivity,but also the decrease of drought resistance.This study analyzed both function and regulatory mechanism of lincRNA13853 in plant drought stress response.The main research results are as follows:1.LincRNA13853 positively regulates Arabidopsis drought stress toleranceLincRNA13853 is located on chromosome 4 in Arabidopsis thaliana and have 786 nucleotides(nt).Compared with wild-type Arabidopsis,lincRNA13853 loss-of-function mutants exhibited the reduced insensitivity to exogenous ABA and drought stress.Moreover,water loss rate of lincRNA13853 loss-of-function mutants is faster than Col-0.And based on measurements on stomatal aperture index of lower epidermis of plant rosette leaves,we inferred that lincRNA13853 may influences the transpiration of plants through adjusting stomatal morphology,leading to the change of plant drought tolerance.2.LincRNA13853 is involved in the regulation of gene transcription levelLincRNA13853 was unidirectionally transcribed through applying the strand-specific reverse transcription PCR.Then,lincRNA13853 was found to be mainly enriched in nucleus according to the analysis of lincRNA13853 distribution in plant cells through combing nuclear-cytoplasmic fractionation with qRT-PCR(Quantitative Real-time PCR).Therefore,we suspect that lincRNA13853 regulates plant drought response at the transcriptional level.In addition,the expression of lincRNA13853 was found to be suppressed by exogenous ABA and PEG.3.RBP7 is a protein interacted with lincRNA13853RBP7 was found to interact with lincRNA13853 by tRSA RNA pull-down and yeast three-hybrid screening.Then,prokaryotic expression and TriFC experiments were used to further prove that RBP7 interacted with lincRNA13853 in vitro and in vivo.RBP7 was expressing in both nucleus and cytoplasm via Arabidopsis subcellular localization experiment,but it interacted with lincRNA13853 in the nucleus according to TriFC results.4.ABA2 is the lincRNA13853 target geneIn order to further explore the molecular mechanism of lincRNA13853 regulating plant drought stress response,we performed RNA-sequencing and qRT-PCR and found that lincRNA13853 positively regulated the expression of ABA2 which is a key gene for ABA synthesis.Based on phenotypical analysis,both water loss rates and stomatal aperture index for aba2 and lincRNA13853 mutants were higher than Col-0,and the phenotype of aba2 mutant was consistent with previous studies.This indicates that lincRNA13853 affects plant drought tolerance by positively regulating ABA2 expression.In summary,in model plant Arabidopsis thaliana,lincRNA13853 mainly enrich in nuclear,and it positively regulates Arabidopsis drought stress response by regulating the expression of ABA2 in synergy with RBP7.Studying both function and molecular mechanism of lincRNA13853 in plant responses to drought stress not only have great theoretical significances for revealing the mechanism of plant drought response,but also provide the theoretical basis and new gene recourse for improving crop drought tolerance. |
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