Knockdown of LjALD1, AGD2‐like defense response protein 1, influences plant growth and nodulation in Lotus japonicus. Issue 11 (19th June 2014)

• Record Type: Journal Article
• Authors: Chen, Wei; Li, Xueliu; Tian, Lu; Wu, Pingzhi; Li, Meiru; Jiang, Huawu; Chen, Yaping; Wu, Guojiang
• Is Part Of: Journal of integrative plant biology. Volume 56:Issue 11(2014)
• Page Start: 1034
• Page End: 1041
• Publication Date: 2014-06-19
• Subjects: Plants -- Periodicals; Plants -- China -- Periodicals; Electronic journals; 580.5
• DOI: 10.1111/jipb.12211
• Languages: English
• ISSNs: 1672-9072

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="jipb12211-sec-0001" sec-type="section"> <p>The discovery of the enzyme <italic>L, L</italic>‐diaminopimelate aminotransferase (LL‐DAP‐AT, EC 2.6.1.83) uncovered a unique step in the L‐lysine biosynthesis pathway in plants. In <italic>Arabidopsis thaliana</italic>, LL‐DAP‐AT has been shown to play a key role in plant‐pathogen interactions by regulation of the salicylic acid (SA) signaling pathway. Here, a full‐length cDNA of LL‐DAP‐AT named as <italic>LjALD1</italic> from <italic>Lotus japonicus</italic> (Regel) Larsen was isolated. The deduced amino acid sequence shares 67% identity with the <italic>Arabidopsis</italic> aminotransferase AGD2‐LIKE DEFENSE RESPONSE PROTEIN1 (AtALD1) and is predicted to contain the same key elements: a conserved aminotransferase domain and a pyridoxal‐5'‐phosphate cofactor binding site. Quantitative real‐time PCR analysis showed that <italic>LjALD1</italic> was expressed in all <italic>L. japonicus</italic> tissues tested, being strongest in nodules. Expression was induced in roots that had been infected with the symbiotic rhizobium <italic>Mesorhizobium loti</italic> or treated with SA agonist benzo‐(1, 2, 3)‐thiadiazole‐7‐carbothioic acid. <italic>LjALD1</italic> Knockdown exhibited a lower SA content, an increased number of infection threads and nodules, and a slight reduction in nodule size. In addition, compared with wild‐type, root growth was increased and shoot growth was suppressed in <italic>LjALD1</italic> RNAi plant lines. These results indicate that LjALD1 may play important roles in plant development and nodulation via SA signaling in <italic>L. japonicus</italic>.</p> </sec> </abstract>