Figure 7.

MADS8 function in temperature-dependent pistil regulation is conserved between barley and rice. A) Pistil phenotypes of DJ (WT) and Osmads8 mutants grown at control (28 °C average) and high (34 °C average) temperatures. ca, carpel; ep, extra pistil; lo, lodicule; pi, pistil; sl, sterile lemma; st, stamen; sti, stigma. Scale bars, 900 μm. B) Pistil number in Osmads8 florets grown at different temperatures. C) Semi-thin sections of stage 12 DJ and Osmads8 pistils at 28 or 34 °C. ca, carpel; ec, extra carpel; ov, ovule. Scale bars, 100 μm. D) Proposed model of HvMADS8-mediated pistil development regulation at high temperatures. In WT flowers, MADS8 binds target genes to induce ovule initiation and FM termination at the appropriate developmental stage under a specific high-temperature signaling pathway. In the absence of MADS8, continued FM development triggers the repeated formation of extra carpels in the innermost whorl. fm, floral meristem; pa, palea.