The role of auxins and cytokinins in the mutualistic interaction between Arabidopsis and Piriformospora indica

0322258 - ÚEB 2009 RIV US eng J - Journal Article
Vadassery, J. - Ritter, C. - Venus, Y. - Camehl, I. - Varma, A. - Shahollari, B. - Novák, Ondřej - Strnad, Miroslav - Ludwig-Mueller, J. - Oelmueller, R.
The role of auxins and cytokinins in the mutualistic interaction between Arabidopsis and Piriformospora indica.
[Role auxinů a cytokininů ve vzájemné interakci mezi Arabidopsis a Piriformospora indica.]
Molecular Plant-Microbe Interactions. Roč. 21, č. 10 (2008), s. 1371-1383. ISSN 0894-0282. E-ISSN 1943-7706
Institutional research plan: CEZ:AV0Z50380511
Keywords : plant-microbe interaction * Sebacinaceae * LATERAL ROOT-FORMATION * GENE-EXPRESSION
Subject RIV: CE - Biochemistry
Impact factor: 4.136, year: 2008

Arabidopsis growth and reproduction are stimulated by the endophytic fungus Piriformospora indica. The fungus produces low amounts of auxins, but the auxin levels and the expression of auxin-regulated genes are not altered in colonized roots. Also, mutants with reduced auxin levels (ilr1-1, nit1-3, tfl2, cyp79 b2b3) respond to R indica. However, the fungus rescues the dwarf phenotype of the auxin overproducer sur1-1 by converting free auxin into conjugates, which also results in the downregulation of the auxin-induced IAA6 and the upregulation of the P indica-induced LRR1 gene. The fungus produces relatively high levels of cytokinins, and the cytokinin levels are higher in colonized roots compared with the uncolonized controls. trans-Zeatin cytokinin biosynthesis and the CRE1/AHK2 receptor combination are crucial for P indica-mediated growth stimulation, while mutants lacking cis-zeatin, impaired in other cytokinin receptor combinations, or containing reduced cytokinin levels respond to the fungus. Since root colonization is not affected in the cytokinin mutants, we propose that cytokinins are required for P indica-induced growth promotion. Finally, a comparative analysis of the phytohormone mutants allows the conclusion that the response to P indica is independent of the architecture and size of the roots.

Byl studován vliv endofytní houby Piriformospora indica na růst a reprodukci Arabidopsis. Byly měřeny hladiny auxinů a cytokininů u houby, v nenapadených i napadených kořenech Arabidopsis (mutantech i netransgenních rostlinnách), výsledky porovnány a diskutovány. Nakonec, srovnávací analýza fytohormonových mutantů vedla k závěru , že odpověď na P. indica je nezávislá na stavbě i velikost kořenů.
Permanent Link: http://hdl.handle.net/11104/0170574