Identification And Expression Analysis Of NAC Transcription Factor In Latex Cells Of Hevea Brasiliensis

Rubber tree(Hevea brasiliensis)is the only commercial source of natural rubber.Natural rubber is one of the secondary metabolites and stored in the laticifer cells of rubber tree.cis-1,4-polyisoprene is the main component of natural rubber which is synthesized by mevalonate pathway.The general rubber biosynthetic metabolic pathway has been revealed in rubber tree,but the molecular regulation mechanism of natural rubber biosynthesis is unclear.NAC transcription factors are plant-specific transcription factors that have a variety of biological functions.NAC transcription factors play an important role in plant growth and development,cell differentiation,xylem formation,hormone regulation,and defense against a variety of biological and abiotic stresses.However,little is known about this gene family in rubber tree.In this study,we identified 128 NAC genes(named HbNACl to HbNAC128)in the latest rubber tree genom.A total of 52 HbNACs were identified in the laticifer cells from the rubber tree latex transcriptome.Among of 52 HbNACs identified in the laticifer cells,18 HbNACs were higher in laticifers.The expression of HbNAC4,HbNAC6,HbNAC7,HbNAC19,HbNAC46,HbNAC62,HbNAC65,HbNAC127 and HbNACl28 were up-regulated by JA.The expression of HbNAC4,HbNAC6,HbNAC7,HbNAC19,HbNAC34,HbNAC37,HbNAC46,HbNAC62,HbNAC65 and HbNAC127 were significantly affected by ET.The expression levels of HbNAC2,HbNAC4,HbNAC6,HbNAC7,HbNAC19,HbNAC24,HbNAC62 and HbNAC65 were significantly up-regulated by ABA,while theexpression of HbNAC21,HbNAC34,HbNAC37,HbNAC67 and HbNACl12 were down-regulated by ABA.The interaction of HbNAC2 and promoter of HbSRPP,HbFDP,HbHRT was identified in yeast,which could regulated the expression of HbSRPP,HbFDP and HbHRT at the transcriptional level.The results suggested that HbNAC2 may be involved in the regulation of natural rubber biosynthesis.