Effects of the endophyte Piriformospora indica on growth, physiology and water relations of tobacco (Nicotiana tobacum ).

摘要

In the current study, wildtype and transgenic tobacco constitutively over-expressing Arabidopsis aquaporins PIP 1;4 and PIP 2;5 were grown in association with the endophyte Piriformospora indica. Root hydraulic conductivity along with various physiological parameters and aquaporin expression were studied in conjunction with growth. Growth promotion was observed in inoculated wildtype and PIP 2;5 over-expression plants, while water relation parameters were not observed to change in any of the genotypes. Quantified expression levels of four aquaporins were not changed in inoculated wildtype plants; however immunolocalization techniques revealed a possible increase in PIP 1 aquaporins in exodermal tissues of the associated plants. It was concluded that the growth promoting benefits of the fungus were due to factors other than influencing water relations and modulation of aquaporins studied. Moreover, it was interpreted that PIP 1;4 over-expression may inhibit growth promotion in inoculated plants, although the mechanisms of that role remains unclear.