title: A comparative study on Ca content and distribution in two Gesneriaceae species reveals distinctive mechanisms to cope with high rhizospheric soluble calcium.
abstract: Excessive Ca is toxic to plants thus significantly affects plant growth and species distribution in Ca-rich karst areas. To understand how plants survive high Ca soil, laboratory experiments were established to compare the physiological responses and internal Ca distribution in organ, tissue, cell, and intracellular levels under different Ca levels for Lysionotus pauciflorus and Boea hygrometrica, two karst habitant Gesneriaceae species in Southwest China. In the controlled condition, L. pauciflorus could survive as high as 200 mM rhizospheric soluble Ca, attributed to a series of physiological responses and preferential storage that limited Ca accumulation in chloroplasts of palisade cells. In contrast, B. hygrometrica could survive only 20 mM rhizospheric soluble Ca, but accumulated a high level of internal Ca in both palisade and spongy cells without disturbance on photosynthetic activity. By phenotype screening of transgenic plants expressing high Ca-inducible genes from B. hygrometrica, the expression of BhDNAJC2 in A. thaliana was found to enhance plant growth and photosynthesis under high soluble Ca stress. BhDNAJC2 encodes a recently reported heat shock protein (HSP) 40 family DnaJ-domain protein. The Ca-resistant phenotype of BhDNAJC2 highlights the important role of chaperone-mediated protein quality control in Ca tolerance in B. hygrometrica. Taken together, our results revealed that distinctive mechanisms were employed in the two Gesneriaceae karst habitants to cope with a high Ca environment.
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, The Chinese Academy of Sciences Beijing, China ; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences Beijing, China ; College of Life Sciences, University of Chinese Academy of Sciences Beijing, China.
authors.forename: Wenlong
authors.initials: W
authors.lastname: Li
authors.affiliation: Key Laboratory of Bio-Resource and Eco-Environment, Ministry of Education, College of Life Sciences, Sichuan University Chengdu, China.
authors.forename: Falun
authors.initials: F
authors.lastname: Xu
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, The Chinese Academy of Sciences Beijing, China.
authors.forename: Shixuan
authors.initials: S
authors.lastname: Chen
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, The Chinese Academy of Sciences Beijing, China.
authors.forename: Zhennan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, The Chinese Academy of Sciences Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, The Chinese Academy of Sciences Beijing, China.
authors.forename: Yukuan
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, The Chinese Academy of Sciences Beijing, China.
authors.forename: Meijing
authors.initials: M
authors.lastname: Li
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, The Chinese Academy of Sciences Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors.forename: Yongxiu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Bio-Resource and Eco-Environment, Ministry of Education, College of Life Sciences, Sichuan University Chengdu, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, The Chinese Academy of Sciences Beijing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Deng
keywords: Boea hygrometrica; Lysionotus pauciflorus; chaperon; heat shock protein; high Ca stress; karst plant; photosynthesis and the environment