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POSTERS: Plant defense response

Investigation of a salicylic acid elicitor formulation in the bacterial leaf blight disease of rice using Synchrotron-based FTIR microspectroscopy
Wannaporn Thepbandit - suranaree university of technology. Supatcharee Siriwong- Synchrotron Light Research Institute, Kanjana Thumanu- Synchrotron Light Research Institute, Toan Le- Can Tho University, Natthiya Buensanteai- Suranaree University of Technology, Dusit Athinuwat- Faculty of Science and Technology, T

We investigated the resistance of rice to bacterial leaf blight (Xanthomonas oryzae pv. Oryzae) induced by a formulation including salicylic acid and inert ingredients (Ricemate®). A Synchrotron Radiation-based Fourier-Transform Infra-Red (SR-FTIR) microspectroscopy technique was used to detect biochemical changes at the sub-cellular level. Rice plants were sprayed with SA-Ricemate® or with water as a control, the plants were inoculated, and disease severity was recorded. Rice leaf supernatant was used to determine salicylic acid (SA) content. Control and treated rice leaf samples were subsequently cut and subjected to SR-FTIR and spectra were collected. SA-Ricemate® reduced disease severity by approximately 41%, 54% and 60% at 7, 14 and 21 days after inoculation, respectively. The accumulation of SA showed an increase of approximately 50% at 24 hr after inoculation. In addition, the variation of biomolecular structure and intensity from average spectra showed higher intensity of CH2, CH3 from lipid groups (3000-2800 cm?1), C=O from pectin (1740 cm?1) as well as C=O, N-H from protein amide I and amide II on treated rice leaf. These results suggested that an elicitor formulation could increase disease resistant by inducing defense compounds such as SA and possibly phenolic, lipid and protein compounds. SR-FTIR may be a useful tool to study the plant defense mechanisms at sub-cellular level.