Heterosis of Biomass Production in Arabidopsis. Establishment during Early Development

Abstract

Heterosis has been widely used in agriculture to increase yield and to broaden adaptability of hybrid varieties and is applied to an increasing number of crop species. We performed a systematic survey of the extent and degree of heterosis for dry biomass in 63 Arabidopsis accessions crossed to three reference lines (Col-0, C24, and Nd). We detected a high heritability (69%) for biomass production in Arabidopsis. Among the 169 crosses analyzed, 29 exhibited significant mid-parent-heterosis for shoot biomass. Furthermore, we analyzed two divergent accessions, C24 and Col-0, the F1 hybrids of which were shown to exhibit hybrid vigor, in more detail. In the combination Col-0/C24, heterosis for biomass was enhanced at higher light intensities; we found 51% to 66% mid-parent-heterosis at low and intermediate light intensities (60 and 120 μmol m−2 s−1), and 161% at high light intensity (240 μmol m−2 s−1). While at the low and intermediate light intensities relative growth rates of the hybrids were higher only in the early developmental phase (0–15 d after sowing [DAS]), at high light intensity the hybrids showed increased relative growth rates over the entire vegetative phase (until 25 DAS). An important finding was the early onset of heterosis for biomass; in the cross Col-0/C24, differences between parental and hybrid lines in leaf size and dry shoot mass could be detected as early as 10 DAS. The widespread occurrence of heterosis in the model plant Arabidopsis opens the possibility to investigate the genetic basis of this phenomenon using the tools of genetical genomics.

Methylation interactions in Arabidopsis hybrids require RNA-directed DNA methylation and are influenced by genetic variation

“…To examine the effects of RdDM pathway on hybrid vigor genetically, we compared F1 hybrids derived from the nrpd1nrpe1 double mutant with F1 hybrids from WT plants, focusing on several traits related to early seedling growth vigor, such as leaf and rosette sizes. Consistent with previous reports (29,30), F1 seedlings from the WT crosses showed obvious heterosis compared with both Col and C24 parents in plant and leaf sizes (P < 0.0001, t test; Fig. 7).…”

Hybrid mimics and hybrid vigor in Arabidopsis

“…heterosis | TCM | epigenetics | transregulation | transcriptome I n Arabidopsis some ecotypes with similar genome sequences produce F1 hybrids with large increases in vegetative and reproductive yields (1,2). These results appear to be at variance with the generalization that the larger the genetic distance between parents, the greater the hybrid vigor (3); however, the Arabidopsis ecotypes have different epigenomes that may be important for hybrid vigor (4).…”

A Role for CHH Methylation in the Parent-of-Origin Effect on Altered Circadian Rhythms and Biomass Heterosis inArabidopsisIntraspecific Hybrids

“…This parent-of-origin effect on biomass vigor was also observed in other reciprocal F1 hybrids between Columbia-0 (Col-0) and C24 or between Col-0 and Ler (Miller et al, 2012), although the vigor level was low in the latter. The variable degree of biomass vigor among different hybrids may reflect genotypic effects (Meyer et al, 2004;Chen, 2010). Collectively, these data suggest a parent-of-origin effect on biomass heterosis.…”

“…Biomass heterosis has been obviously observed in reciprocal F1 hybrids between Arabidopsis C24 and Landsberg erecta (Ler) (Meyer et al, 2004;Groszmann et al, 2011;Shen et al, 2012). The reciprocal hybrids accumulated 50 and 100% more starch in rosette leaves at dusk (ZT15; Zeitgeber time 0 [ZT0] = dawn) than their parents C24 and Ler ( Figure 1A).…”