Kajian Ketahanan Tanaman Padi Berpigmen (Oryza sativa L.) terhadap Penyakit Blas Melalui PendekatanTranskriptomik dan Metabolomik

EGGIE F. GINANJAR , Dr. Tri Rini Nuringtyas, M.Sc ; Dr. Widodo, S.P., M.Sc

2016 | Tesis | S2 Bioteknologi

Tujuan penelitian adalah mengetahui ekspresi gen PBZ1 dan PR1 terkait ketahanan terhadap blas dan membandingkan profil metabolomik kultivar tanaman padi berpigmen tahan dengan rentan terhadap penyakit blas. Penelitian diawali non-choice bioassay pada enam kultivar padi: Ireng Tinggi (CI), Ireng INDMIRA (IM), Abang Wangi (AW), Abang Tinggi (AT), Asahan (AS) dan Kencana Bali (KB) terhadap penyakit blas. Koleksi sampel daun dilakukan pada hari setelah inokulasi (HSI) ke-0, 3 dan 7 untuk analisis ekspresi gen PBZ1 dan PR1 dengan RT-PCR. Analisis PR1, marker Systemic Acquired Resistance (SAR), dilanjutkan dengan qPCR untuk mengetahui level ekspresi gen. Analisis metabolomik dilakukan dengan NMR pada tanaman mock terpilih mewakili padi tahan, moderat tahan dan rentan. Data NMR diolah dengan M-NOVA dan dianalisis PCA untuk mengetahui perbedaan profil metabolitnya. Hasil kultivar yang tahan: CI, AW, AT, AS, moderat tahan: IM, dan rentan: KB. Ekspresi gen PBZ1 dan PR1 ditemukan pada semua kultivar padi perlakuan. Gen PBZ1 mulai terdeteksi pada HSI-0 untuk kultivar tahan, sedangkan kultivar rentan HSI-3. Ekpresi PR1 terdeteksi pada semua hari perlakuan. Hasil qPCR menunjukan level ekspresi gen PR1 tertinggi dimulai pada HSI-3 pada kultivar CI dan AW. Hasil analisis metabolomik, kultivar rentan berada di kuadran positif, terpisah dari kultivar lainnya dengan variansi 53,46%, kultivar moderat tahan mengelompok ditengah, dan kultivar tahan pada kuadran negatif dari komponen utama 1. Metabolit kultivar tahan didominasi oleh senyawa fumarat, tirosin, dan fenilalanin. Ekspresi gen PBZ1 dan PR1 pada kultivar tahan terekspresi lebih cepat dibandingkan kultivar rentan. Profil metabolomik kultivar tahan memiliki hubungan erat dengan SAR melalui jalur sikimat.

This research aimed to reveal the expression of PBZ1 and PR1, and compare metabolomic profile between pigmented rice resistant to blast disease with susceptible one. Firstly, non-choice bioassay of six cultivars was performed on Ireng Tinggi (CI), Ireng INDMIRA (IM), Abang Wangi (AW), Abang Tinggi (AT), Asahan (AS) and Kencana Bali (KB) against blast disease. The leaves were collected at 0, 3, and 7 days post-inoculation. Samples were subjected for RT-PCR to evaluate the expression gen of PBZ1 and PR1. The PR1 analysis was continued by qPCR. Metabolomics analysis was conducted by NMR on selected mock cultivars. NMR data was processed by M-NOVA and PCA to determine metabolites responsible to the resistant character. The resistant cultivars were CI, AW, AT and AS, and moderate resistance cultivars IM, while susceptible cultivar KB. The PBZ1 and PR1 were expressed on all cultivars and PBZ1 was induced faster in resistant cultivar than susceptible. PR1 was detected in all samples. qPCR analysis showed the highest level of gene expression for PR1 started on 3rd day in CI and AW. Metabolomics analysis indicated that susceptible cultivar placed separated from others cultivars with 53.46% variance. The moderate resistant cultivar clustered in the middle, and resistant cultivars were in negative quadrant of the PC 1. It can be concluded that PBZ1 and PR1 were expressed in both resistant and susceptible cultivars, but the resistants were induced earlier than susceptible rice in pathogenesis situation. Metabolomic profile of resistant-pigmented rice showed a closely related metabolite for SAR mechanism.

Kata Kunci : Padi berpigmen, blas, SAR, transkriptomik, metabolomik