Altered growth and improved resistance of Arabidopsis against Pseudomonas syringae by overexpression of the basic amino acid transporter AtCAT1

作者：Yang Huaiyu; Postel Sandra; Kemmerling Birgit; Ludewig Uwe^*

来源：Plant, Cell and Environment, 2014, 37(6): 1404-1414.

DOI：10.1111/pce.12244

• amino acid permease
• cationic amino acid
• lysine
• salicylic acid
• systemic acquired resistance

Amino acid transporters in plants are crucial for distributing amino acids between plant organs and cellular compartments. The H+-coupled plasma membrane transporter CAT1 (cationic amino acid transporter 1) facilitates the high-affinity uptake of basic amino acids. The uptake of lysine (Lys) via the roots was not altered in loss-of-function mutants, in accordance with the minor expression of CAT1 in roots, but plants ectopically overexpressing CAT1 incorporated Lys at higher rates. Exogenous Lys inhibited the primary root of Arabidopsis, whereas lateral roots were stimulated. These effects were augmented by the presence or absence of CAT1. Furthermore, the total biomass of soil-grown plants ectopically overexpressing CAT1 was reduced and the time to flowering was accelerated. These effects were accompanied by only minor changes in the overall amino acid profile. Interestingly, CAT1 belongs to a specific small cluster of nitrogen-containing metabolite transporter genes that are rapidly up-regulated upon infection with Pseudomonas syringae and that may participate in the systemic response of plants to pathogen attack. The overexpression of CAT1 indeed enhanced the resistance to the hemibiotrophic bacterial pathogen P.syringae via a constitutively activated salicylic acid (SA) pathway, which is consistent with the developmental defects and the resistance phenotype. %26lt;br%26gt;The cationic amino acid transporter gene CAT1 was identified as part of a transcriptional pathogen response and its over-expression negatively affected the biomass, but improved the defense against pathogens via salicylic acid.

• 出版日期2014-6