Overexpression of Camellia sinensis H1 histone gene confers abiotic stress tolerance in transgenic tobacco

Abstract

Overexpression of CsHis in tobacco promoted chromatin condensation, but did not affect the phenotype. It also conferred tolerance to low-temperature, high-salinity, ABA, drought and oxidative stress in transgenic tobacco. H1 histone, as a major structural protein of higher-order chromatin, is associated with stress responses in plants. Here, we describe the functions of the Camellia sinensis H1 Histone gene (CsHis) to illustrate its roles in plant responses to stresses. Subcellular localization and prokaryotic expression assays showed that the CsHis protein is localized in the nucleus, and its molecular size is approximately 22.5 kD. The expression levels of CsHis in C. sinensis leaves under various conditions were investigated by qRT-PCR, and the results indicated that CsHis was strongly induced by various abiotic stresses such as low-temperature, high-salinity, ABA, drought and oxidative stress. Overexpression of CsHis in tobacco (Nicotiana tabacum) promoted chromatin condensation, while there were almost no changes in the growth and development of transgenic tobacco plants. Phylogenetic analysis showed that CsHis belongs to the H1C and H1D variants of H1 histones, which are stress-induced variants and not the key variants required for growth and development. Stress tolerance analysis indicated that the transgenic tobacco plants exhibited higher tolerance than the WT plants upon exposure to various abiotic stresses; the transgenic plants displayed reduced wilting and senescence and exhibited greater net photosynthetic rate (Pn), stomatal conductance (Gs) and maximal photochemical efficiency (Fv/Fm) values. All the above results suggest that CsHis is a stress-induced gene and that its overexpression improves the tolerance to various abiotic stresses in the transgenic tobacco plants, possibly through the maintenance of photosynthetic efficiency.

Na2CO3-responsive mechanisms in halophyte Puccinellia tenuiflora roots revealed by physiological and proteomic analyses

“…The down-regulated histone H2B gene was also found in T. hispida roots under NaHCO 3 for 48 h13. This indicates that dynamic chromosome assembly exists in alkali-stressed roots, which would facilitate chromosome remodeling for alkali-specific gene expression regulation67. In our results, transcription factors PURα1 and RRM were increased in Na 2 CO 3 -stressed roots (Table 1).…”

Global Transcriptional Analysis Reveals the Complex Relationship between Tea Quality, Leaf Senescence and the Responses to Cold-Drought Combined Stress in Camellia sinensis

“…“ Yunnan Dayecha ,” was used as plant material. It has been identified to possess high tolerance to both cold and drought stress (Wang et al, 2014; Zhou et al, 2014). Two-year-old tea plants were culture-grown under a 12-h light (25°C)/12-h dark (20°C) photoperiod with 1800 Lx photos m −2 ·s −2 light intensity and 75% humidity in growth chamber for 2 weeks.…”

Stress-induced structural changes in plant chromatin

“…This is particularly interesting in light of the role described for H2A.Z as a thermosensor [46], and suggests that H2A.Z may have a more general role in chromatin responses to stress [68]. Furthermore, plants express a specific class of stress-inducible H1 variants [61,69], which, upon overexpression, confers tolerance to several abiotic stresses [70]. Whether the plant-specific histone variant H2A.W, which is associated with heterochromatin [71 ], is involved in stress-induced decondensation needs to be investigated.…”