Collaborative expression of FLOWERING LOCUS C in heat- tolerant cauliflower

Introduction -Cauliflower (Brassica oleracea var. botrytis) is suitable for growing in a temperate climate and could be grown in tropical or sub-trop-ical regions in the cool season. Due to the impact of global warming, cauliflower cultivation has become a challenge. At temperatures over 30 & DEG;C, the curds show physiological disorders resulting in low qual-ity and economic loss. The study aimed to determine the curd development and FLOWERING LOCUS C (FLC) gene expressions in heat-tolerant and non-heat -tolerant cauliflower, which could provide helpful information for cauliflower selection in the future. Materials and methods -Cauliflower seedlings were treated at 26 & DEG;C in growth chambers for two weeks. After the stem apices reached curd initiation, plants were exposed to continuous temperatures of 26, 30, and 34 & DEG;C for 5 weeks. BoFLC gene detections were in the 2nd and 4th weeks after temperature treatments. In the 3rd and 5th weeks, apex investigations were con-ducted by tissue dissection with microscope obser-vation. Results -Cauliflower 'Winner' showed heat tolerance at 26 & DEG;C and 30 & DEG;C, and curd development was induced. BoFLC1, BoFLC2, and BoFLC5 transcript levels decreased after curd initiation. 'Early 45' also formed visible curd at 26 & DEG;C with decreasing BoFLC1 and BoFLC2 transcript levels and the lowest level of BoFLC5. The high BoFLC1 and BoFLC5 in 'PI 244664' acted as a potent inhibitor at the curd development stage at 26-34 & DEG;C. Conclusion - BoFLC in heat-tolerant lines might go through a collaborative expression via the non-vernalization pathway and establish an adaptive mechanism at relatively high temperatures (26-30 & DEG;C).

Automated summary

Cauliflower cultivation is facing challenges due to global warming, with temperatures over 30°C leading to physiological disorders and economic loss. This study investigated curd development and FLOWERING LOCUS C (FLC) gene expressions in heat-tolerant and non-heat-tolerant cauliflower. The results showed that heat-tolerant varieties and 'Early 45' could develop curds at 26°C and 30°C, while 'PI 244664' inhibited curd development with high levels of BoFLC1 and BoFLC5 expression at 26-34°C.