The Genetic basis of transgenerational plasticity

Transgenerational plasticity (TGP) is an efficient mechanism by which parental responses are used as cues to pre-condition offspring for the environment they are likely to encounter. TGP has received renewed attention as a rapid and efficient mechanism to adapt to environmental change. A meta-analysis further revealed how pervasive it was across plants and animals, potentially adaptive or not. In the case of A. thaliana, TGP was shown to affect most traits tested but was also shown to differ across genotypes, which suggests that there is a genetic basis for TGP. Two studies have investigated the effect of specific genes on heat-induced TGP before first flowering in A. thaliana [Chen et al. (2014) PNAS and Migicovsky et al. (2014) Plant Signal. Behav.]. These showed the capacity of the DICER-LIKE genes (DCL) and FLOWERING LOCUS T (FT) to induce parental effects on rosette diameter and seed dormancy, respectively. Despite testing only a few genetic backgrounds, there was a strong genetic basis for TGP. In both cases TGP was environment-dependent with greater differences observed among the controls than the stressed plants. In addition, the intensity of the TGP decreased with the number of generations of exposure to stress. TGP, therefore is environment-sensitive and most importantly is genetically variable, making it an excellent target on which selection can operate. We analysed the germination pattern of 140 natural accessions whose mother plants had been exposed to different climate but only during the vegetative stage. Our results reveal a significant TGP for dormancy and strong differences among genotypes. A Genome-wide association study suggested the involvement of the Phytochrome B locus as primary candidate for the control of TGP.

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