Cloning and functional characterization of PjPORB, a member of the POR gene family in Pseudosasa japonica cv. Akebonosuji

Abstract

In angiosperms, NADPH: protochlorophyllide oxidoreductase (POR) catalyzes the photoreduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide), the only light-dependent step in chlorophyll biosynthesis. There is a wide variety of gene organization and light-and development-dependent regulatory mechanisms for the POR genes. In this study, a POR homologue, designated PjPORB, was isolated from Pseudosasa japonica cv. Akebonosuji, which is a cultivar of high ornamental value in landscape due to its unique green-white striped leaf phenotype. The full-length PjPORB cDNA was 1567 bp long with a 1185 bp ORF that encoded 394 amino acids. Multiple amino acid sequence alignment showed that the putative PjPORB shared a high similarity to POR homologues from other plant species, and that the cofactor (NADPH)-binding motif and active site motif in particular were highly conserved among all the PORs. Further, PjPORB was overexpressed in Arabidopsis thaliana; and the Pchlide contents of the genetically modified plants were reduced to a larger extent than that of wild type plants, thereby indicating its important role in Pchlide photoreduction. In real-time quantitative RT-PCR analysis, PjPORB was expressed at higher levels in leaf samples than in culms and roots, and showed a first increasing-then decreasing expression pattern during the development of white, stripe, and green leaf samples, thus indicating its essential role in leaf development. Although the mRNA levels for PjPORB did not differ considerably among white, stripe, and green leaf samples within the two almost same earlier developmental stages, its expression levels in the late leaf developmental stage fell into two distinct classes: high expression levels in strip and green leaf samples, and low expression levels in white leaf. Collectively, these expression data suggested that PjPORB may be involved in the leaf color variation for P. japonica cv. Akebonosuji.

Ethyl methanesulfonate mutant library construction in Gossypium hirsutum L. for allotetraploid functional genomics and germplasm innovation

“…1 sample was mutated at PORB, and the no. 2 sample was mutated at POR1 as the previously reported leaf color-related genes (Jiang and Zhou, 2016;Lu et al, 2019).…”

FvMYB108, a MYB Gene from Fragaria vesca, Positively Regulates Cold and Salt Tolerance of Arabidopsis

“…When 9–10 true leaves had grown, 30 seedlings with good growth were selected and divided evenly into 6 groups for the following treatment: the first group served as a control and grew normally in the greenhouse incubator; the second group was subjected to low-temperature stress in a −4 °C incubator; the third group contained irrigated seedlings with 200 mM NaCl for salt stress; the fourth group used 15% PEG6000 for irrigation to simulate drought stress; the fifth group was subjected to high-temperature stress in a 37 °C incubator; 100 μM ABA irrigated the sixth group of seedlings for ABA treatment. According to previous studies, samples were taken from young leaves, old leaves, roots, and stems at 0, 1, 2, 4, 8, and 12 h and frozen in liquid nitrogen before being stored at −80 °C [ 9 , 43 ].…”

Overexpression of a Fragaria vesca 1R-MYB Transcription Factor Gene (FvMYB114) Increases Salt and Cold Tolerance in Arabidopsis thaliana

“…The other 3 groups were treated with 15% PEG6000 (Solarbio, P8250, Beijing, China), 200 mM NaCl (Solarbio, LA0200, Beijing, China) and 100 uM ABA (Solarbio, A8060, Beijing, China), respectively, to simulate drought, salt and ABA stress. To determine the cold treatment results, the roots and young leaves of all 6 groups’ seedlings were sampled at 0, 1, 3, 5, 7, 9 and 11 h, when they were immediately frozen with liquid nitrogen and then stored at −80 °C for subsequent RNA extraction [ 57 ].…”