Heritability of temperature-mediated flower size plasticity in Arabidopsis thaliana

Abstract

Phenotypic plasticity is a heritable trait that provides sessile organisms a strategy to rapidly mitigate negative effects of environmental change. Yet, we have little understanding of the mode of inheritance and genetic architecture of plasticity in different focal traits relevant to agricultural applications. This study builds on our recent discovery of genes controlling temperature-mediated flower size plasticity in Arabidopsis thaliana and focuses on dissecting the mode of inheritance and combining ability of plasticity in the context of plant breeding. We created a full diallel cross using 12 A. thaliana accessions displaying different temperature-mediated flower size plasticities, scored as the fold change between two temperatures. Griffing's analysis of variance in flower size plasticity indicated that non-additive genetic action shapes this trait and pointed at challenges and opportunities when breeding for reduced plasticity. Our findings provide an outlook of flower size plasticity that is important for developing resilient crops for future climates.

Keywords: Arabidopsis thaliana; heritability; inheritance patterns; plasticity; temperature.

Fig. 1.

Mean average flower diameters and temperature-mediated flower size plasticities in the parental accessions used for diallel crosses. Flower diameters were measured at each temperature and compared using a two-sample two-tailed t-test. * indicates p-values < .1, corrected by Benjamini–Hochberg when n = 12. Flower size plasticity is quantified as the ratio between the two biological replicates of plants grown at 23 and 17°C. Accessions are ordered from smallest to largest average temperature-mediated flower size plasticity. Error bars represent standard deviation of the mean for the FDs and the plasticities measured.

Fig. 2.

Crosses showing non-additive inheritance of temperature-mediated flower size plasticity. All crosses shown exhibited a significant difference in calculated FC plasticity compared to their respective MPV at a false discovery rate of 10% (shown by the dashed line, p-values were adjusted according to the Benjamini–Hochberg, when n = 28. All crosses showed negative dominance. (a) Six showed dominance towards maternal and three showed dominance towards parental alleles. The reciprocal crosses between Lag1-2 and Lecho-1 showed negative overdominance (b), whereby the average temperature-mediated flower size plasticity FC was significantly greater than both parental phenotypes.

Fig. 3.

Heritability and box plots for flower diameter plasticities of parent and F1 hybrids. (a) Father–offspring regression to quantify heritability (i.e., twice the regression coefficient). (b)Wilcoxon ranked rum test applied showing no significant differences between the groups (W = 690, p-value = .0487). Levene’s test for homogeneity suggests the variances cannot be distinguished between the two groups (F = 0.1415, p-value = .7074).