Fruit set is inhibited by adverse temperatures,with consequences on yield.We isolated a tomato mutant producing fruits under non-permissive hot temperatures and identified the causal gene as SIHB15A,belonging to class...Fruit set is inhibited by adverse temperatures,with consequences on yield.We isolated a tomato mutant producing fruits under non-permissive hot temperatures and identified the causal gene as SIHB15A,belonging to classⅢhomeodomain leucine-zipper transcription factors.SIHB15A,loss-of-function mu-tants display aberrant ovule development that mimics transcriptional changes occurring in fertilized ovules and leads to parthenocarpic fruit set under optimal and non-permissive temperatures,in field and greenhouse conditions.Under cold growing conditions,SIHB15A is subjected to conditional haploinsufficiency and recessive dosage sensitivity controlled by microRNA 166(miR166).Knockdown of SIHB15A alleles by miR166 leads to a continuum of aberrant ovules correlating with parthenocarpic fruit set.Consistent with this,plants harboring an Slhb15a-miRNA166-resisiant allele developed normal ovules and were unable to set parthenocarpic fruit under cold conditions.DNA affinity purification sequencing and RNA-sequencing analyses revealed that SIHB15A is a bifunctional transcription factor expressed in the ovule integument.SIHB15A binds to the promoters of auxin-related genes to repress auxin signaling and to the promoters of ethylene-related genes to activate their expression.A survey of tomato genetic biodiversity identified pat and pat-1,two historical parthenocarpic mutants,as alleles of SIHB15A.Taken together,our findings demonstrate the role of SIHB15A as a sentinel to prevent fruit set in the absence of fertilization and provide a mean to enhance fruiting under extreme temperatures.展开更多
基金INRAE,CNRS,and the LabEx Saclay Plant Sciences-SPS(ANR-10-LABX-40-SPS)The A.B.team received funding from the European Research Council(ERC-SEXYPARTH,341076)from the Horizon 2020 research and innovation program(TOMRES,727929).
文摘Fruit set is inhibited by adverse temperatures,with consequences on yield.We isolated a tomato mutant producing fruits under non-permissive hot temperatures and identified the causal gene as SIHB15A,belonging to classⅢhomeodomain leucine-zipper transcription factors.SIHB15A,loss-of-function mu-tants display aberrant ovule development that mimics transcriptional changes occurring in fertilized ovules and leads to parthenocarpic fruit set under optimal and non-permissive temperatures,in field and greenhouse conditions.Under cold growing conditions,SIHB15A is subjected to conditional haploinsufficiency and recessive dosage sensitivity controlled by microRNA 166(miR166).Knockdown of SIHB15A alleles by miR166 leads to a continuum of aberrant ovules correlating with parthenocarpic fruit set.Consistent with this,plants harboring an Slhb15a-miRNA166-resisiant allele developed normal ovules and were unable to set parthenocarpic fruit under cold conditions.DNA affinity purification sequencing and RNA-sequencing analyses revealed that SIHB15A is a bifunctional transcription factor expressed in the ovule integument.SIHB15A binds to the promoters of auxin-related genes to repress auxin signaling and to the promoters of ethylene-related genes to activate their expression.A survey of tomato genetic biodiversity identified pat and pat-1,two historical parthenocarpic mutants,as alleles of SIHB15A.Taken together,our findings demonstrate the role of SIHB15A as a sentinel to prevent fruit set in the absence of fertilization and provide a mean to enhance fruiting under extreme temperatures.
