Autophagy is induced during plant grafting for wound healing

Abstract

O_LIGrafting is an important technique in agriculture to obtain several good traits such as high disease tolerance and high yield by exchanging root system. However, the underlined cellular processes to compensate the wound damage and repair tissues were largely unknown. C_LIO_LIWe analyzed two graft combinations: Nicotiana benthamiana (Nb) homograft as a compatible, wound repairing model and Nb heterograft with Arabidopsis thaliana (At) as an incompatible and more stressful model, which we recently identified as an exceptional maintainable interfamily grafting. C_LIO_LIIn both graft combinations, nutrient loss was observed in gene expression after grafting, where the level of nutrient loss was more sever in heterografts. Transmission electron micrographs of Nb/At heterografts suggested that microautophagy was induced in cells near the graft boundary. In At seedling micrografting, the fluorescence of autophagy protein marker GFP-ATG8 was highly observed at graft junction especially in cambial region. In At atg2 mutant homografts, growth after grafting decreased compared with wild-type homografts. Moreover, when NbATG5 knocked-down Nb scion was grafted to At stock, the successful rate of grafting was significantly decreased. C_LIO_LIAltogether, these results suggest that component of autophagy is induced during grafting and has a role in wound healing. C_LI