Search

Citrus rootstock can modify plant growth and enhance stress resistance. There are many genotypes and species used as citrus rootstocks. Although multiple citrus rootstocks whole genome sequence and transcriptome databases have previously been published, no suitable internal reference genes have been investigated for standardization of gene expression via quantitative real-time PCR. Here we reported the first systematic and comprehensive analysis of reference genes for quantitative real-time PCR standardization in various citrus rootstocks. The expression stability of ten candidate reference genes in diverse sample subsets of flooding, drought, alkaline and cold treatments was evaluated using four statistical algorithms, geNorm, NormFinder, BestKeeper and ΔCt method. The results demonstrated that the expression stability of reference genes varied under different experimental conditions. In addition, normalization of gene expression of 9-cis-epoxycarotenoid dioxygenase 3 (NCED 3), involved in abscisic acid biosynthesis, was conducted to further confirm the reliability of the reference genes. Overall, EF-1α, DIM 1, GAPC and UBC expressed much more stably. ACTIN and GAPDH were not recommended for normalization in given experimental conditions due to low stability. Our main contribution was to identify reference genes with suitable and stable expression in citrus rootstocks varied across selected experimental conditions. Furthermore, these results will provide valuable information for future research on citrus rootstocks. [ABSTRACT FROM AUTHOR]

Main conclusion: FaMAPK5 and FaMAPK10 genes were involved in ABA-mediated strawberry fruit ripening and could enhance the antioxidant capacity by increasing non-enzymatic components and enzymatic antioxidants. Mitogen-activated protein kinases (MAPKs) are the key proteins involved in plant stress response by activating an antioxidant defense system, which cooperates with plant hormones. However, the involvement of MAPKs in the regulation of strawberry fruit ripening and resistance is unclear. In this study, two genes, FaMAPK5 and FaMAPK10, were isolated, and their expression pattern and function analysis were conducted. The results showed FaMAPK5 and FaMAPK10 were expressed in all tested tissue/organ types and reached the highest expression level at the white stage during strawberry fruit development and ripening. Transient overexpression of FaMAPK5 and FaMAPK10 increased the fruit anthocyanin, abscisic acid (ABA), total sugar, and glucose contents. ABA and especially hydrogen peroxide (H2O2) treatment induced the production of large amounts of H2O2 and noticeably increased the expression levels of FaMAPK5 and FaMAPK10 in strawberry fruit, while the reduced glutathione (GSH) had the opposite effect. The level of total phenol and activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) significantly increased in FaMAPK5 overexpression fruit, and increased activities of SOD and CAT were observed in FaMAPK10 overexpression fruit. In addition, Botrytis cinerea treatment showed that overexpression of FaMAPK5 conferred retarded disease symptom development and enhanced fruit disease resistance. Our research revealed that FaMAPK5 and FaMAPK10 might participate in ABA-mediated H2O2 signaling in regulating strawberry fruit ripening and resistance. [ABSTRACT FROM AUTHOR]