title: Malate secretion from the root system is an important reason for higher resistance of Miscanthus sacchariflorus to cadmium.
abstract: Miscanthus is a vigorous perennial Gramineae genus grown throughout the world as a promising bioenergy crop and generally regarded as heavy metal tolerant due to its ability to absorb heavy metals. However, little is known about the mechanism for heavy metal tolerance in Miscanthus. In this study, two Miscanthus species (Miscanthus sacchariflorus and Miscanthus floridulus) exhibiting different cadmium (Cd) sensitivity were used to address the mechanisms of Cd tolerance. Under the same Cd stress, M. sacchariflorus showed higher Cd tolerance with better growth and lower Cd accumulation in both shoots and roots than M. floridulus. The malate (MA) content significantly increased in root exudates of M. sacchariflorus following Cd treatment while it was almost unchanged in M. floridulus. Cellular Cd analysis and flux data showed that exogenous MA application markedly restricted Cd influx and accumulation while an anion-channel inhibitor (phenylglyoxal) effectively blocked Cd-induced MA secretion and increased Cd influx in M. sacchariflorus, indicating that MA secretion could alleviate Cd toxicity by reducing Cd uptake. The genes of malate dehydrogenases (MsMDHs) and Al-activated malate transporter 1 (MsALMT1) in M. sacchariflorus were highly upregulated under Cd stress, compared with that in M. floridulus. The results indicate that Cd-induced MA synthesis and secretion efficiently alleviate Cd toxicity by reducing Cd influx in M. sacchariflorus.
authors: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
authors: Haipeng
authors: H
authors: Guo
authors: Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China.
authors: Xue
authors: X
authors: Feng
authors: Department of Forestry, Ningbo Academy of Agricultural Sciences, Ningbo, 315040, China.
authors: Chuntao
authors: C
authors: Hong
authors: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
authors: Houming
authors: H
authors: Chen
authors: Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China.
authors: Fanrong
authors: F
authors: Zeng
authors: Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, Hangzhou, 311300, China.
authors: Bingsong
authors: B
authors: Zheng
authors: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
authors: Dean
authors: D
authors: Jiang
mesh_terms: D027321:Anion Transport Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism / Q000633:toxicity*; D008291:Malate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D008293:Malates / Q000378:metabolism* / Q000494:pharmacology; D010658:Phenylglyoxal / Q000494:pharmacology; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D006109:Poaceae / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D012989:Soil Pollutants / Q000378:metabolism / Q000633:toxicity*; D013312:Stress, Physiological
chemical_list: D027321:Anion Transport Proteins; D008293:Malates; D010940:Plant Proteins; D012989:Soil Pollutants; D002104:Cadmium; D008291:Malate Dehydrogenase; D010658:Phenylglyoxal