Plants are frequently exposed to herbivory and mechanical damage that result in wounding.Two fundamental strategies,regeneration and healing,are employed by plants upon wounding.How plants make different decisions and...Plants are frequently exposed to herbivory and mechanical damage that result in wounding.Two fundamental strategies,regeneration and healing,are employed by plants upon wounding.How plants make different decisions and how wound healing is sustained until the damaged tissues recover are not fully understood.In this study,we found that local auxin accumulation patterns,determined by wounding modes,may activate different recovery programs in wounded tissues.Wounding triggers transient jasmonic acid(JA)signaling that promotes lignin deposition in the first few hours after wounding occurs.This early response is subsequently relayed to ABA signaling via MYC2.The induced JA signaling promotes ABA biosynthesis to maintain the expression of RAP2.6,a key factor for sustained lignin biosynthesis and the later wound-healing process.Our findings provide mechanistic insights into how plants heal from wounding and clarify the molecular mechanisms that underlie the prolonged healing process following wounding.展开更多
Redox Responsive Transcription Factor1 （RRTF1） in Arabidopsis is rapidly and transiently upregulated by H202, as well as biotic- and abiotic-induced redox signals. RRTF1 is highly conserved in angio- sperms, but its...Redox Responsive Transcription Factor1 （RRTF1） in Arabidopsis is rapidly and transiently upregulated by H202, as well as biotic- and abiotic-induced redox signals. RRTF1 is highly conserved in angio- sperms, but its physiological role remains elusive. Here we show that inactivation of RRTF1 restricts and overexpression promotes reactive oxygen species （ROS） accumulation in response to stress. Transgenic lines overexpressing RRTF1 are impaired in root and shoot development, light sensitive, and susceptible to Alternaria brassicae infection. These symptoms are diminished by the beneficial root endophyte Piriformospora indica, which reduces ROS accumulation locally in roots and systemi- cally in shoots, and by antioxidants and ROS inhibitors that scavenge ROS. More than 800 genes were detected in mature leaves and seedlings of transgenic lines overexpressing RRTF1; ∽40% of them have stress-, redox-, ROS-regulated-, ROS-scavenging-, defense-, cell death- and related functions. Bioinformatic analyses and in vitro DNA binding assays demonstrate that RRTF1 binds to GCC-box-like sequences in the promoter of RRTFl-responsive genes. Upregulation of RRTF1 by stress stimuli and H202 requires WRKY18/40/60. RRTF1 is co-regulated with the phylogenet- ically related RAP2.6, which contains a GCC-box-like sequence in its promoter, but transgenic lines overexpressing RAP2.6 do not accumulate higher ROS levels. RRTF1 also stimulates systemic ROS accumulation in distal non-stressed leaves. We conclude that the elevated levels of the highly conserved RRTF1 induce ROS accumulation in response to ROS and ROS-producing abiotic and biotic stress signals.展开更多
基金supported bygrants from the National Natural ScienceFoundation of China(32400270 and 32425050).
文摘Plants are frequently exposed to herbivory and mechanical damage that result in wounding.Two fundamental strategies,regeneration and healing,are employed by plants upon wounding.How plants make different decisions and how wound healing is sustained until the damaged tissues recover are not fully understood.In this study,we found that local auxin accumulation patterns,determined by wounding modes,may activate different recovery programs in wounded tissues.Wounding triggers transient jasmonic acid(JA)signaling that promotes lignin deposition in the first few hours after wounding occurs.This early response is subsequently relayed to ABA signaling via MYC2.The induced JA signaling promotes ABA biosynthesis to maintain the expression of RAP2.6,a key factor for sustained lignin biosynthesis and the later wound-healing process.Our findings provide mechanistic insights into how plants heal from wounding and clarify the molecular mechanisms that underlie the prolonged healing process following wounding.
文摘Redox Responsive Transcription Factor1 （RRTF1） in Arabidopsis is rapidly and transiently upregulated by H202, as well as biotic- and abiotic-induced redox signals. RRTF1 is highly conserved in angio- sperms, but its physiological role remains elusive. Here we show that inactivation of RRTF1 restricts and overexpression promotes reactive oxygen species （ROS） accumulation in response to stress. Transgenic lines overexpressing RRTF1 are impaired in root and shoot development, light sensitive, and susceptible to Alternaria brassicae infection. These symptoms are diminished by the beneficial root endophyte Piriformospora indica, which reduces ROS accumulation locally in roots and systemi- cally in shoots, and by antioxidants and ROS inhibitors that scavenge ROS. More than 800 genes were detected in mature leaves and seedlings of transgenic lines overexpressing RRTF1; ∽40% of them have stress-, redox-, ROS-regulated-, ROS-scavenging-, defense-, cell death- and related functions. Bioinformatic analyses and in vitro DNA binding assays demonstrate that RRTF1 binds to GCC-box-like sequences in the promoter of RRTFl-responsive genes. Upregulation of RRTF1 by stress stimuli and H202 requires WRKY18/40/60. RRTF1 is co-regulated with the phylogenet- ically related RAP2.6, which contains a GCC-box-like sequence in its promoter, but transgenic lines overexpressing RAP2.6 do not accumulate higher ROS levels. RRTF1 also stimulates systemic ROS accumulation in distal non-stressed leaves. We conclude that the elevated levels of the highly conserved RRTF1 induce ROS accumulation in response to ROS and ROS-producing abiotic and biotic stress signals.
