Z innia (Zinnia elegans) belongs to the family Asteraceae. It is a summer annual cut flower and getting popular due to its several colorful blooms. It is originated from Central America and Mexico. "Blue Point" and "Oklahoma" are the most grown zinnia cultivars are considered the colorfully blooms and better performance (Dole, 1999). Zinnia is annual and perennial plants and its flowers display uniform colors, bright, strong stems with long vase life and disease resistant plants. Zinnia is the most familiar species and a plant of hot and warm climate. Conventionally, taller cultivars of Zinnia are used in beds and borders, for cut flowers but the dwarf cultivars in window planters, and containers ( Jana and Pal, 1991). Zinnia is propagated through seeds and seeds are directly sown in pots, and then transplanted in to field. Zinnia required 23-27 o C for germination in five to seven days.

Flavonols have been shown to respond to a variety of abiotic stresses in plants, including cold stress. Higher total flavonoid content was found in non-heading Chinese cabbage (NHCC, Brassica campestris (syn. Brassica rapa) ssp. chinensis) after cold stress. A non-targeted metabolome analysis showed a significant increase in flavonol content, including that of quercetin and kaempferol. Here, we found that an R2R3–MYB transcription factor, BcMYB111, may play a role in this process. BcMYB111 was up-regulated in response to cold treatment, with an accompanying accumulation of flavonols. Then, it was found that BcMYB111 could regulate the synthesis of flavonols by directly binding to the promoters of BcF3H and BcFLS1. In the transgenic hairy roots of NHCC or stable transgenic Arabidopsis, overexpression of BcMYB111 increased flavonol synthesis and accumulation, while these were reduced in virus-induced gene silencing lines in NHCC. After cold stress, the higher proline content and lower malondialdehyde (MDA) content showed that there was less damage in transgenic Arabidopsis than in the wild-type (WT). The BcMYB111 transgenic lines performed better in terms of antioxidant capacity because of their lower H2O2 content and higher superoxide dismutase (SOD) and peroxidase (POD) enzyme activities. In addition, a key cold signaling gene, BcCBF2, could specifically bind to the DRE element and activate the expression of BcMYB111 in vitro and in vivo. The results suggested that BcMYB111 played a positive role in enhancing the flavonol synthesis and cold tolerance of NHCC. Taken together, these findings reveal that cold stress induces the accumulation of flavonols to increase tolerance via the pathway of BcCBF2–BcMYB111–BcF3H/BcFLS1 in NHCC.

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The plant IQD gene family is responsive to a variety of stresses. In this study, we studied the structural features and functions of the gene BrIQD35 in Chinese cabbage, a member of the IQD gene family.• BrIQD35 was cloned and shown to contain an IQ motif. Transient expression of BrIQD35 indicated that it was localized on the plasma membrane and was significantly upregulated under drought and salt stress in Chinese cabbage. To further identify the function of BrIQD35, it was heterologously overexpressed in Nicotiana benthamiana. Although there was no significant difference between BrIQD35-overexpressed and wild-type (WT) plants under salt stress, WT N. benthamiana showed more wilting than the BrIQD35-overexpressed plants under drought stress.• Since the IQ motif has been annotated as a CaM binding site, yeast two-hybrid assays were used to explore the interaction between BrIQD35 and CaM. The results indicated that BrIQD35 interacts weakly with CaMb, but not with CaMa, suggesting that BrIQD35 may function through the Ca 2+ -CaMb pathway.• The findings reveal a novel gene involved in drought tolerance, which is important for plant breeding and quality improvement for Chinese cabbage.

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