Metabolite Profiling of Black Rice (Oryza sativa L.) following Xanthomonas oryzae pv. oryzae Infection
Ema Nur Hidayah1, Febri Adi Susanto3, Tri Joko2, Yekti Asih Purwestri1,3, Tri Rini Nuringtyas 1,3
1 Faculty of Biology, Universitas Gadjah Mada, Yogyakarta, Indonesia
2 Faculty of Agriculture, Universitas Gadjah Mada, Yogyakarta, Indonesia
3 Research Center for Biotechnology, Universitas Gadjah Mada, Yogyakarta
Abstract
Black rice is usually consumed as a functional food owing to its high anthocyanin content, which functions as an antioxidant. However, bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) has resulted in reduction in yield. Black rice has been reported to have a higher resistance to BLB than other local black rice cultivars. Here, we aimed to determine the metabolite responses of several black rice cultivars following Xoo infection. Two local black rice cultivars, Melik and Pari Ireng, and two white rice cultivars, IR64 and Java14, were treated with Xoo pathotype IV and a mock negative control (physical damage). GC-MS was used for the metabolite profiling analysis, followed by the quantification of total phenolic concentration (TPC) and total flavonoid concentration (TFC). Across all cultivars, the results revealed that following Xoo infection, there were significantly higher concentrations of primary metabolites including sugars, sugar alcohols, fatty acids, glycerol, and some organic acids. In Pari Ireng and Melik, sugars including fructose, mannose, and gluco-hexodialdose were present in a significantly higher concentration following the infection than before it. The infection significantly increased the TPC as follows: Java14 (0.841 % ± 0.005 %), followed by Pari Ireng (0.809 % ± 0.005%), Melik (0.771 % ± 0.003%), and IR64 (0.514 % ± 0.006%). Regarding TFC, the incerease following the infection was greater for Pari Ireng (0.517 ± 0.005 μm/g) than for Melik (0.465 ± 0.001 μm/g).
Keywords: Bacterial leaf blight, pigmented rice, GC-MS, metabolomics, Xoo infection
Topic: Environmentally Sustainable Agriculture