Aluminum-induced ethylene production is associated with inhibition of root elongation in Lotus japonicus L.
Inhibition of root elongation by toxic aluminum (Al(3+)) occurs rapidly and is one of the most distinct and earliest symptoms of Al toxicity. To elucidate mechanism underlying Al(3+)-induced inhibition of root elongation, we investigated the involvement of ethylene in Al(3+)-induced inhibition of root elongation using the legume model plants Lotus japonicus and Medicago truncatula. Root elongation of L. japonicus and M. truncatula was rapidly inhibited by exposure to AlCl(3). A similar rapid inhibition of root elongation by the ethylene-releasing substance, ethephon, and the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), was also observed. The Al(3+)-induced inhibition of root elongation was substantially ameliorated in the presence of antagonists of ethylene biosynthesis [Co(2+) and aminoethoxyvinylglycine (AVG)]. Al(3+) increased the activity of ACC oxidase (ACO), and induced a rapid evolution of ethylene from root apices and expression of genes of ACC synthase (ACS) and ACO. These findings suggest that induction of ethylene evolution resulting from up-regulation of ACS and ACO plays a critical role in Al(3+)-induced inhibition of root elongation.
Sun
Pei
P
South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China.
Tian
Qiu-Ying
QY
Zhao
Min-Gui
MG
Dai
Xiao-Yan
XY
Huang
Jian-Hui
JH
Li
Ling-Hao
LH
Zhang
Wen-Hao
WH
D000077410:Aluminum Chloride; D017607:Aluminum Compounds / Q000494:pharmacology*; D000594:Amino Acid Oxidoreductases / Q000235:genetics / Q000378:metabolism; D002712:Chlorides / Q000494:pharmacology*; D005030:Ethylenes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D000070116:Lotus / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D008190:Lyases / Q000235:genetics / Q000378:metabolism; D046913:Medicago truncatula / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D017607:Aluminum Compounds; D002712:Chlorides; D005030:Ethylenes; D000077410:Aluminum Chloride; C036216:ethylene; D000594:Amino Acid Oxidoreductases; C059460:1-aminocyclopropane-1-carboxylic acid oxidase; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase