Calcium and calcium receptor CAS promote Arabidopsis thaliana de‐etiolation

Abstract

As a second messenger, the free cytosolic calcium ion (Ca(2+)) plays important roles in many biochemical and physiological processes including photosynthesis in plants. In this study, we investigated morphological changes, chlorophyll accumulation and chloroplast development during early photomorphogenesis in etiolated seedlings of both Arabidopsis thaliana wild type (WT) and those with the antisense of CAS, a calcium sensor (CASas). Seedlings were grown at high, medium and low Ca(2+) concentrations to identify the roles of Ca(2+) and CAS in de-etiolation and chloroplast development. The results demonstrated that Ca(2+) and CAS are correlated with de-etiolation of A. thaliana after light exposure. High Ca(2+) significantly increased chlorophyll content and improved chloroplast development in both A. thaliana WT and CASas etiolated seedlings during de-etiolation. The analysis by western blot and real-time fluorescent quantitative polymerase chain reaction indicated that the expression levels of CAS mRNA and protein were upregulated by white light and external Ca(2+) significantly. Etiolated CASas plants showed much lower chlorophyll content and delay of chloroplast development as compared with WT plants, indicating that CAS functions in de-etiolation. All together, we concluded that the de-etiolation in A. thaliana was promoted by the high Ca(2+) concentration and CAS expression to a certain extent.

Proteomic Analysis Reveals Differences in Tolerance to Acid Rain in Two Broad-Leaf Tree Species, Liquidambar formosana and Schima superba

“…Our previous study also reported that Ca addition dramatically alleviated the negative effects of AR on seed germination, seedling growth and photosynthesis [3]. Free Ca ion within cell is a second messenger for conveying internal and external signals by Ca sensors that subsequently regulate diverse cellular processes in plants [17]. Calmodulin (CaM) and calcium-dependent protein kinase (CDPK), two major types of Ca sensor, play important roles in Ca signaling and further response to diverse stresses in plants [51].…”

“…Chlorophyll was extracted from approximately 0.1 g fresh leaf slices directly into 10 ml ice-cold acetone (80%, v/v). The chlorophyll content (mg g −1 fresh weight (FW)) was determined as described previously [17].…”

Proteomic Analysis Reveals Nitric Oxide Functions in Promoting Etiolated Barley Seedlings Greening

“…At least three seedlings and more than 40 chloroplasts for each time point were analyzed (Huang et al, 2012). The samples were then washed with phosphate buffer solution (0.1 M, pH 7.0), and post-fixed for 4 h with 1% OsO 4 at room temperature.…”

“…The total Chl content (mg g -1 fresh weight [FW]) in barley seedlings at each time point of illumination was measured according to Huang et al (2012). Absorption of the extract was measured at 663 and 645 nm with a spectrometer (Cary 50 UV-VIS, Varian, Mulgrave, Australia).…”

“…Mitogen-activated protein kinase kinase (spot 67 [MAPKK]) can be modulated by G protein signal. Moreover, cytosolic Ca 2+ , an important second messenger, functions in mediating many physiological processes in plants (Huang et al, 2012). In this study, the abundance of MAPKK were increased by NO (Supplemental Table S1), indicating that NO-stimulated G protein signaling pathway may play an essential role in promoting greening of barley seedlings.…”