The Functional And Evolutionary Investigation Of A Cotton Long Non-coding RNA Gene DAN1 In Drought Tolaerance

To explore the drought stress regulation and improve cotton drought stress endurance has always been one of the most important questions to be solved.Long non-coding RNA(lncRNA)has been shown to be involved in abiotic stress response.However,the molecular basis of lncRNA in drought tolerance in crops remains largely unknown.In our previous study,we found that the genome shock of whole genome duplication(WGD)and interspecies hybridization introduces great variation in the transcriptome in both coding and non-coding genes.The vigor from hybridization and polyploidization includes the adaptability to a wide range of environments with biotic or abiotic stresses.We hypothesize that the non-coding genes stimulated by genome shock are involved with the stress tolerance in the new species after polyploidization.To validate the hypothesis,we screen the lncRNAs in allotetraploid upland cotton and identified a lincRNA,GhDAN1(Drought associated Non-coding RNA 1),which is involved with drought tolerance control.The gene highly expressed in leaves and stems and the expression is induced by high temperature and suppressed by salt.GhDAN1 has multiple alternative splicing isoforms.The transcript of GhDAN1 was predominantly located in nucleus.The transcriptome analysis reveal that,the GhDAN1 suppressive lines of VIGS treatment exhibited very subtle impacts on the expression of the flanking genes up-and downstream of GhDAN1.These data indicated that GhDAN1 might take a role in drought tolerance control in trans regulation.GhDAN1 is located in A subgenome of allotetraploid genome and originate from A diploid ancestor.The expression of DAN1 was activated only in allotetraploid species,which indicated DAN1 was stimulated after the polyploidization event.The DAN1 expression in A diploid and allotetraploid species was negatively correlated with the level of drought tolerance.These data suggested DAN1 activity was directly involved with the drought tolerance dynamics of the cotton lineage evolution.The role of DAN1 in cotton evolution and drought tolerance regulation suggests a novel mechanism of neofunctionalization of non-coding genes stimulated by the genome shock of WGD in natural evolution.This presented study confirmed the function of GhDANl and the mechanism of drought tolerance regulation.A novel mechanism of lncRNA in the vigor of intraspecific hybridization and whole genome duplication(WGD)lncRNA is revealed.