Down-regulation of PvTRX1h increases nodule number and affects auxin, starch, and metabolic fingerprints in the common bean (Phaseolus vulgaris L.)

作者：Barraza Aaron; Lorena Coss Navarrete Evelia; Carlos Vizuet de Rueda Juan; Martinez Aguilar Keren; Luis Hernandez Chavez Jose; Juan Ordaz Ortiz Jose; Winkler Robert; Tiessen Axel; Alvarez Venegas Raul^*

来源：Plant Science, 2018, 274: 45-58.

DOI：10.1016/j.plantsci.2018.05.006

• PvTRX1h
• Auxin
• Amyloplasts
• Common bean

The legume-rhizobium symbiotic relationship has been widely studied and characterized. However, little information is available about the role of histone lysine methyltransferases in the legume-rhizobium interaction and in the formation of nitrogen-fixing nodules in the common bean. Thus, this study aimed to gain a better understanding of the epigenetic control of nodulation in the common bean. Specifically, we studied the role of PvTRX1h, a histone lysine methyltransferase coding gene, in nodule development and auxin biosynthesis. Through a reverse genetics approach, we generated common bean composite plants to knock-down PvTRX1h expression.
Here we found that the down-regulation of PvTRX1h increased the number of nodules per plant, but reduced the number of colony-forming units recovered from nodules. Genes coding for enzymes involved in the synthesis of the indole-3-acetic acid were up-regulated, as was the concentration of this hormone. In addition, PvTRX1h down-regulation altered starch accumulation as determined by the number of amyloplasts per nodule. Metabolic fingerprinting by direct liquid introduction-electrospray ionization-mass spectrometry (DLI-ESI-MS) revealed that the root nodules were globally affected by PvTRX1h down-regulation. Therefore, PvTRX1h likely acts through chromatin histone modifications that alter the auxin signaling network to determine bacterial colonization, nodule number, starch accumulation, hormone levels, and cell proliferation.

• 出版日期2018-9