Moderate salt treatment alleviates ultraviolet-B radiation caused impairment in poplar plants.
The effects of moderate salinity on the responses of woody plants to UV-B radiation were investigated using two Populus species (Populus alba and Populus russkii). Under UV-B radiation, moderate salinity reduced the oxidation pressure in both species, as indicated by lower levels of cellular H2O2 and membrane peroxidation, and weakened the inhibition of photochemical efficiency expressed by O-J-I-P changes. UV-B-induced DNA lesions in chloroplast and nucleus were alleviated by salinity, which could be explained by the higher expression levels of DNA repair system genes under UV-B&salt condition, such as the PHR, DDB2, and MutSα genes. The salt-induced increase in organic osmolytes proline and glycine betaine, afforded more efficient protection against UV-B radiation. Therefore moderate salinity induced cross-tolerance to UV-B stress in poplar plants. It is thus suggested that woody plants growing in moderate salted condition would be less affected by enhanced UV-B radiation than plants growing in the absence of salt. Our results also showed that UV-B signal genes in poplar plants PaCOP1, PaSTO and PaSTH2 were quickly responding to UV-B radiation, but not to salt. The transcripts of PaHY5 and its downstream pathway genes (PaCHS1, PaCHS4, PaFLS1 and PaFLS2) were differently up-regulated by these treatments, but the flavonoid compounds were not involved in the cross-tolerance since their concentration increased to the same extent in both UV-B and combined stresses.
School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
Xuan
X
Ma
School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
Yong-Bin
YB
Ou
School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
Yong-Feng
YF
Gao
Groupe de Recherche en Physiologie végétale (GRPV), Earth and Life Institute-Agronomy (ELI-A), Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium.
Stanley
S
Lutts
Key Laboratory of Biogeography and Bioresources, Xinjiang Institute of Ecology and Geography, Chinese Academy of Science, Urumqi 830011, China.|University of Chinese Academy of Sciences, Beijing 100039, China.
Tao-Tao
TT
Li
School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
Yang
Y
Wang
School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
Yong-Fu
YF
Chen
Key Laboratory of Biogeography and Bioresources, Xinjiang Institute of Ecology and Geography, Chinese Academy of Science, Urumqi 830011, China.|University of Chinese Academy of Sciences, Beijing 100039, China.
Yu-Fang
YF
Sun
School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.|Key Laboratory of Biogeography and Bioresources, Xinjiang Institute of Ecology and Geography, Chinese Academy of Science, Urumqi 830011, China.
Yin-An
YA
Yao
D000222:Adaptation, Physiological; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development* / Q000528:radiation effects; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D032107:Populus / Q000187:drug effects / Q000254:growth & development* / Q000528:radiation effects; D055049:Salt Tolerance / Q000528:radiation effects*; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological / Q000187:drug effects* / Q000528:radiation effects; D014466:Ultraviolet Rays / Q000009:adverse effects*
D010940:Plant Proteins; D012965:Sodium Chloride