The physiological characteristics and associated gene expression of sugar cane inoculated with Leifsonia xyli subsp. xyli.

Ratoon stunt is a very important disease affecting sugar cane that is caused by the bacterium Leifsonia xyli subsp. xyli ( Lxx). We inoculated cuttings of the sugar cane varieties Badila and GT11 with Lxx to investigate the effects of this disease on their growth, physiological characteristics and associated gene differential expression, sampling after 150, 180 and 210 days following treatment. In addition, to further explore the colonization of this bacterium at transcription and translation levels, we designed a number of primers from the sequence of an Lxx-specific gene and performed quantitative real-time PCR ( qRT- PCR) for Lxx18460 to detect accumulation in plants. Total proteins from diseased plants were detected using Western blotting with an Lxx-specific gene monoclonal antibody. The results of this study show that bacterial levels gradually increased with plant growth following inoculation. Specifically, plant height, stalk diameter, single stalk weight and water potential all decreased as a result of ratoon stunt infection, while membrane permeability and amino acid content increased in Lxx-infected plants compared to the control. The expression of PAL, ZFP and NBS- LRR genes all also increased in plants subject to ratoon stunt stress; this result suggests that these genes are involved in sugar cane responses to Lxx infection. [ABSTRACT FROM AUTHOR]