No abstract

In order to explore the association of long-term high light (HL) with leaf senescence in wheat, two wheat genotypes Xiaoyan 54 (HL-tolerant) and Jing 411 (HL-sensitive) grown in low light were subjected to HL for 2-8 d. The results showed that 6-8 d of HL led to dramatic decline of chlorophyll content, photochemical efficiency, and activity of Rubisco and antioxidant enzymes. Meanwhile, the content of malondialdehyde (MDA), soluble proteins, soluble sugars, superoxide anion, and ascorbic acid increased markedly. Additionally, the expression of senescence-associated genes (SAGs) was induced by HL. Xiaoyan 54 accumulated less MDA, soluble sugars, and superoxide anions but showed a higher ratio of reduced to oxidized ascorbic acid than that in Jing 411 under long-term HL stress. Moreover, most of the assayed SAGs were less induced in Xiaoyan 54 than that in Jing 411. Altogether, the reduction of antioxidant enzyme activities and accumulation of soluble sugars may result in long-term HL-induced leaf senescence.

Baishouwu (Cynanchum auriculatum) is a kind of critical Chinese herbal medicine. However, compared with the studies of other Chinese herbal medicines, the screening study on the reference genes of C. auriculatum is still the blank. Deterioration of the natural environment severely affects the growth and development of C. auriculatum. This study screened and identified suitable reference genes of C. auriculatum under various stress conditions. Based on qRT-PCR, geNorm, NormFinder, BestKeeper, and RefFinder were used for the expression stability evaluation of 12 potential reference genes from C. auriculatum. The ranking table showed that optimal reference genes included EF2 and SAMDC (heat stress), CYP and TUB-β (cold stress), TUB-α and GAPDH (drought stress), SAMDC and TUB-α (waterlogging stress), along with EF2 and ACT7 (salt stress). These results also demonstrated that under different abiotic stresses, suitable reference genes of plants should be selected for qRT-PCR analysis.

Background Water shortage caused by global warming seriously affects the yield and quality of vegetable crops. β-carotene, the lipid-soluble natural product with important pharmacological value, is abundant in celery. Transcription factor MYB family extensively disperses in plants and plays regulatory roles in carotenoid metabolism and water scarcity response. Results Here, the AgMYB5 gene encoding 196 amino acids was amplified from celery cv. ‘Jinnanshiqin’. In celery, the expression of AgMYB5 exhibited transactivation activity, tissue specificity, and drought-condition responsiveness. Further analysis proved that ectopic expression of AgMYB5 increased β-carotene content and promoted drought tolerance in transgenic Arabidopsis thaliana. Moreover, AgMYB5 expression promoted β-carotene biosynthesis by triggering the expression of AtCRTISO and AtLCYB, which in turn increased antioxidant enzyme activities, and led to the decreased contents of H2O2 and MDA, and the inhibition of O2− generation. Meanwhile, β-carotene accumulation promoted endogenous ABA biosynthesis of transgenic Arabidopsis, which resulted in ABA-induced stomatal closing and delayed water loss. In addition, ectopic expression of AgMYB5 increased expression levels of AtERD1, AtP5CS1, AtRD22, and AtRD29. Conclusions The findings indicated that AgMYB5 up-regulated β-carotene biosynthesis and drought tolerance of Arabidopsis.

Background Water shortage caused by global warming seriously affects the yield and quality of vegetable crop. β-carotene, the lipid-soluble natural product with important pharmacological value, is abundant in celery. Transcription factor MYB family extensively disperses in plants and plays regulatory roles in carotenoid metabolism and water scarcity response. Results Here, AgMYB5 gene encoding 196 amino acids was amplified from celery cv. ‘Jinnanshiqin’. In celery, the expression of AgMYB5 exhibited transactivation activity, tissue specificity, and drought-condition responsiveness. Further analysis proved that ectopic expression of the AgMYB5 increased β-carotene content and promoted drought resistance in transgenic Arabidopsis thaliana. Moreover, AgMYB5 expression promoted β-carotene biosynthesis by triggering the expression of AtCRTISO and AtLCYB, which in turn increased antioxidant enzyme activities, and led to the decreased contents of H2O2 and MDA, and the inhibition of O2− generation. Meanwhile, β-carotene accumulation promoted endogenous ABA biosynthesis of the transgenic Arabidopsis plants overexpression AgMYB5 gene, which resulted in ABA-induced stomatal closing and delayed water loss rate. In addition, ectopic expression of AgMYB5 increased expression levels of AtERD1, AtP5CS1, AtRD22, and AtRD29. Conclusions The findings indicated that AgMYB5 up-regulated β-carotene biosynthesis and drought resistance of Arabidopsis.