COS 224-1 - Family ties: root social physiology within Solanaceae

Abstract: Root–root communication effects on social physiology among Solanaceae relatives were studied along with its effects on plant acclimation to abiotic stress. We examined cherry (C) and field (F) tomato (Solanum lycopersicum) and bell pepper (B) (Capsicum annuum), comprising three degrees of relatedness (DOR): high (H-DOR; CC, FF and BB), medium (M-DOR; CF) and low (L-DOR; CB and FB). Plants were grown either alone or in pairs of similar or different degrees of relatedness on rhizoslides, pots and in a greenhouse with and without salinity stress. Root growth, including the proliferation of fine roots, and respiration increased as the DOR decreased and were highest in paired L-DOR plants. On the other hand, root exudates of L-DOR plants had significantly lower levels of total organic carbon and protein than those of H-DOR plants, indicating different root–root communication between individuals with different DOR. Plants subjected to neighbors were acclimated to salinity stress, depending on the identity of the specific neighbor. Our findings indicate, for the first time, that carbon allocation to root growth, exudation and respiration depends on the degree of genetic relatedness, and that the DOR between individual plants plays a key role in root social physiology and on plant acclimation to abiotic stress.