Cold stress is an important factor that limits grape (Vitis sp.) production around the world. The high expression of osmotically responsive genes 1 (HOS1) protein acts as a repressor of cold-responsive genes in plants. To increase understanding of mechanism regulating cold tolerance in grape, we isolated and characterized a novel HOS1 gene, designated VvHOS1 from ‘Muscat Hamburg’ grapevine (Vitis vinifera). Real-time polymerase chain reaction (PCR) analysis revealed that the expression of VvHOS1 could be induced by the application of exogenous abscisic acid and various abiotic environmental conditions such as low temperature, drought, and salinity. Moreover, VvHOS1 expression could also be induced by cold plus drought conditions (4 °C, 10% polyethylene glycol 6000). In addition, overexpression of VvHOS1 in arabidopsis (Arabidopsis thaliana) decreased the plants’ tolerance to cold, drought, and salt as well as negatively regulated the expression level of two stress-responsive genes, AtRD29A and AtCOR47. The results obtained in this study should help us to elucidate the function of VvHOS1 and understand the cold-responsive pathway in grapevine.
Jitao Li, Nian Wang, Lina Wang, Haiping Xin, and Shaohua Li
Nian Wang, Zhang Chang Qin, Jun-bo Yang, and Jing-li Zhang
Rhododendron delavayi Franch. is an important ornamental plant and often plays a role in natural hybridization with other sympatric species in Rhododendron subgenus Hymenanthes. Fifteen microsatellite loci were developed and characterized in this species. The average allele number of these microsatellites was four per locus, ranging from three to six. The ranges of expected (HE) and observed (HO) heterozygosities were 0.0365 to 0.7091 and 0.0263 to 0.9512, respectively. Cross-species amplification in R. agastum and R. decorum showed that a subset of these markers holds promise for congeneric species study. These sets of markers are potentially useful to investigate the genetic structure and gene flow of R. delavayi and other congeneric species.
Lijuan Wang, Nian-Oine Shi, Murray E. Duysen, and Chiwon W. Lee
Cleistogamy in Salpiglossis sinuatu L. involves a sequence of events, including arrested corolla development, precocious pollen germination inside anther, pollen tube penetration of the pistil, and eventual self fertilization, that takes place. within a tightly closed flower bud. A single dominant gene (C) controls cleistogamy in this plant. During early blooming period, cleistogamous (CC, Cc) plants produce both chasmogamous (open) and cleistogamous (closed) flowers. Enzymes in various tissues of both cleistogamous and chasmogamous buds were detected by isozyme banding patterns in starch gel electrophoresis. The onset of cleistogamy may be signalled in the calyx and corolla tissues in the early stage of flower development. The levels of specific enzymes (PGM, PGI, G-6PD, PGD, MPI) involved in gluconeogenesis, pentose phosphate shunt and glycolysis in both calyx and corolla tissues of the cleistogamous buds were greatly reduced. These enzymes were present in the pistil and anthers of cleistogamous buds and in all floral parts of the chasmogamous buds.