Orchid plants develop protocorms upon germination and produce protocorm-like structures called protocorm-like bodies(PLBs)from protocorms and somatic cells via tissue culture.Protocorm-like bodies have broad technical...Orchid plants develop protocorms upon germination and produce protocorm-like structures called protocorm-like bodies(PLBs)from protocorms and somatic cells via tissue culture.Protocorm-like bodies have broad technical application potential in the orchid industry and their regeneration is a distinct developmental process in the plant kingdom.However,little is known about this unparalleled developmental program.In this study,we identified a PLB-abundant gene,ethylene response factor(ERF),and a transcription factor named Do ERF5,and determined its important role in PLB regeneration in Dendrobium orchid.Overexpression of Do ERF5 in Dendrobium greatly enhanced the PLB regeneration from PLB and stem explants,and upregulated the expression of WOUND-INDUCED DEDIFFERENTIATION(Do WIND)homologs and SHOOT MERISTEMLESS(Do STM),as well as the genes involved in cytokinin biosynthesis(Do IPT)and the cytokinin response factors(Do ARRs).However,silencing Do ERF5 reduced the regeneration rate of PLBs,and downregulated the expression of Do WIND homologs,Do STM and Do ARRs.We demonstrated that Do ERF5 is directly bound to the Do STM promoter and regulates its expression.In addition,overexpression of Do STM in Dendrobium orchid resulted in favorable regeneration of PLBs.Our results clarify that Do ERF5 regulates the regeneration of PLB by enhancing Do STM expression.Our findings provide new insights into how Do ERF5 mediates PLB regeneration and offers technical potential in improving clonal propagation,preservation,and the bioengineering of orchids.展开更多
基金supported by grants from the National Natural Science Foundation of China(Grant No.32071819)Natural Science Foundation of Guangdong Province(Grant No.2021A1515012170)the Key-Area Research and Development Program of Guangdong Province(Grant No.2022B0202080002)。
文摘Orchid plants develop protocorms upon germination and produce protocorm-like structures called protocorm-like bodies(PLBs)from protocorms and somatic cells via tissue culture.Protocorm-like bodies have broad technical application potential in the orchid industry and their regeneration is a distinct developmental process in the plant kingdom.However,little is known about this unparalleled developmental program.In this study,we identified a PLB-abundant gene,ethylene response factor(ERF),and a transcription factor named Do ERF5,and determined its important role in PLB regeneration in Dendrobium orchid.Overexpression of Do ERF5 in Dendrobium greatly enhanced the PLB regeneration from PLB and stem explants,and upregulated the expression of WOUND-INDUCED DEDIFFERENTIATION(Do WIND)homologs and SHOOT MERISTEMLESS(Do STM),as well as the genes involved in cytokinin biosynthesis(Do IPT)and the cytokinin response factors(Do ARRs).However,silencing Do ERF5 reduced the regeneration rate of PLBs,and downregulated the expression of Do WIND homologs,Do STM and Do ARRs.We demonstrated that Do ERF5 is directly bound to the Do STM promoter and regulates its expression.In addition,overexpression of Do STM in Dendrobium orchid resulted in favorable regeneration of PLBs.Our results clarify that Do ERF5 regulates the regeneration of PLB by enhancing Do STM expression.Our findings provide new insights into how Do ERF5 mediates PLB regeneration and offers technical potential in improving clonal propagation,preservation,and the bioengineering of orchids.
