Damage activatesEVG1to suppress vascular differentiation during regeneration inArabidopsis thaliana

Abstract

AbstractPlants possess remarkable regenerative abilities to formde novovasculature after damage and in response to pathogens that invade and withdraw nutrients. To look for common factors that affect vascular formation upon stress, we searched forArabidopsis thalianagenes differentially expressed duringAgrobacteriuminfection, nematode infection and plant grafting. One such gene was cell-wall associated and highly induced by all three stresses. Mutations in it enhanced ectopic xylem formation in Vascular cell Induction culture System Using Arabidopsis Leaves (VISUAL) and enhanced graft formation and was thus namedENHANCER OF VISUAL AND GRAFTING 1(EVG1). Mutatedevg1inhibited cambium development and callus formation yet promoted tissue attachment, syncytium size, phloem reconnection and xylem formation.evg1affected abscisic acid and cell wall responses and was itself down regulated by ABA. We found mutations in a receptor-like gene,RLP44, had the same regeneration phenotype asEVG1mutations including enhancing VISUAL and grafting.evg1andrlp44mutants affected the expression of many genes in common including those important for successful regeneration and vascular formation. We propose thatEVG1integrates information from cutting, wounding or parasitism stresses and functions withRLP44to suppress vascular differentiation during regeneration.