VERNALIZATION1 controls developmental responses of winter wheat under high ambient temperatures (Development)

In bread wheat, the VERNALIZATION 1 (VRN1) gene is induced after cold exposure and short days, promoting flowering.  In some species the vernalization effect of cold temperature can be lost or reversed after a short exposure to a high temperature (∼35°C); this process is referred as de-vernalization. Very little is known about this response or the genetic regulation under variable growth temperatures. Dixon and colleagues exposed 98 bread wheat winter and spring varieties to two different growing temperature conditions (low, LT, and high, HT, temperature) after vernalization. The response was varied; all but one flowered faster under HT. Charger, a winter variety, flowered earlier under LT. Further analysis showed that Charger has a high copy number of VRN-A1 (VRN1 copy in genome A) and the T-type allele was more frequent in Charger compared to the other winter species analyzed. They also found that genes that repress flowering like VRN2 are re-activated under HT during and after vernalization, and this re-activation depended on photoperiod. The results show how the absence of warm is critical for the completion of vernalization but also that the known temperatures for vernalization could be higher than previously thought. (Summary by Cecilia Vasquez-Robinet) Development 10.1242/dev.172684