Identity and provenance of neighbors, genotype-specific traits and abiotic stress affect intraspecific interactions in the annual legume Medicago truncatula

Abstract

O_LIAccounting for intraspecific variation may improve our understanding of species coexistence. However, our knowledge of what factors maintain intraspecific variation is limited. We predicted that 1) a plant grows larger when with non-kin (i.e. different genotypes) than kin (i.e. same genotype) neighbors, 2) abiotic stress alters the outcome of kin vs. non-kin interactions, 3) genetic identity of plants affects composition of soil microbiome. C_LIO_LIWe set up mini-communities of Medicago truncatula, where focal genotypes were grown together with two kin or two non-kin neighbors from different origins. We analyzed how origin, identity of interacting genotypes and abiotic stress affected growth and fruit production. We also analyzed the composition of soil microbial communities. C_LIO_LIFocal plants grew larger in non-kin than in kin mini-communities. This pattern was stronger in low level of abiotic stress and when interacting genotypes were from similar origins. However, genotypic variation in growth and response to competition had a stronger effect on growth than mini-community type. Plant genotype identity did not affect soil microbiome. C_LIO_LIWe find that intraspecific variation is affected by genotype-specific traits and abiotic stress. Geographic, rather than genetic, distance among interacting genotypes affects the outcome of intraspecific interactions. C_LI