Medicago truncatula ecotypes A17 and R108 differed in their response to iron deficiency.
Medicago truncatula Gaertn is a model legume species with a wide genetic diversity. To evaluate the responses of the two M. truncatula ecotypes, the effect of Fe deficiency on ecotype A17 and ecotype R108, which have been widely used in physiological and molecular studies, was investigated. A greater reduction in shoot Fe concentration of R108 plants than that of A17 plants was observed under Fe-deficient conditions. Exposure to Fe-deficient medium led to a greater increase in ferric chelate reductase (FCR) activity in roots of A17 than those of R108 plants, while expression of genes encoding FCR in roots of A17 and R108 plants was similarly up-regulated by Fe deficiency. Exposure of A17 plants to Fe-deficient medium evoked an ethylene evolution from roots, while the same treatment had no effect on ethylene evolution from R108 roots. There was a significant increase in expression of MtIRT encoding a Fe transporter in A17, but not in R108 plants, upon exposure to Fe-deficient medium. Transcripts of MtFRD3 that is responsible for loading of iron chelator citrate into xylem were up-regulated by Fe deficiency in A17, but not in R108 plants. These results suggest that M. truncatula ecotypes A17 and R108 differed in their response and adaptation to Fe deficiency, and that ethylene may play an important role in regulation of greater tolerance of A17 plant to Fe deficiency. These findings provide important clues for further elucidation of molecular mechanism by which legume plants respond and adapt to low soil Fe availability.
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, PR China.
Gen
G
Li
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, PR China.
Baolan
B
Wang
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, PR China.
Qiuying
Q
Tian
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, PR China.
Tianzuo
T
Wang
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, PR China; Research Network of Global Change Biology, Beijing Institutes of Life Sciences, Chinese Academy of Sciences, Beijing, China. Electronic address: whzhang@ibcas.ac.cn.
Wen-Hao
WH
Zhang
D060146:Ecotype; D038181:FMN Reductase / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D000090463:Iron Deficiencies; D046913:Medicago truncatula / Q000033:anatomy & histology / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D018517:Plant Roots / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction
D038181:FMN Reductase; C023903:ferric citrate iron reductase
Ecotype A17; Ecotype R108; Fe deficiency; Ferric chelate reductase activity; Medicago truncatula