Overexpression of OsGID1 Enhances the Resistance of Rice to the Brown Planthopper Nilaparvata lugens

Gibberellins (GAs) play pivotal roles in plant growth and development, and in defenses against pathogens. Thus far, how the GA-mediated signaling pathway regulates plant defenses against herbivores remains largely unknown. In this study, we cloned the rice GA receptor gene OsGID1, whose expression was induced by damage from the brown planthopper (BPH) Niaparvata lugens, mechanical wounding, and treatment with salicylic acid (SA), but not jasmonic acid. The overexpression of OsGID1 (oe-GID1) decreased BPH-induced levels of SA, H2O2, and three SA-pathway-related WRKY transcripts, but enhanced BPH-induced levels of ethylene. Bioassays in the laboratory revealed that gravid BPH females preferred to feed and lay eggs on wild type (WT) plants than on oe-GID1 plants. Moreover, the hatching rate of BPH eggs on oe-GID1 plants was significantly lower than that on WT plants. In the field, population densities of BPH adults and nymphs were consistently and significantly lower on oe-OsGID1 plants than on WT plants. The increased resistance in oe-GID1 plants was probably due to the increased lignin level mediated by the GA pathway, and to the decrease in the expression of the three WRKY genes. Our findings illustrated that the OsGID1-mediated GA pathway plays a positive role in mediating the resistance of rice to BPH.

Optimasi Pretreatment melalui Metode Hydrothermal Pressure dan Pelarut Alkali pada Produksi Bioetanol dari Lemna minor

<p>Produk bioetanol dengan bahan dasar biomassa lignoselulosa perlahan banyak dikembangkan sebagai sumber energi alternatif. Tantangan utama dalam produksi lignoselulosa etanol berada pada tahap <em>pretreatment</em>. <em>Pretreatment</em> merupakan tahap yang memegang peranan penting dalam mendegradasi lignoselulosa menjadi selulosa. Pada penelitian ini digunakan <em>Lemna minor</em> yang merupakan gulma perairan dengan kombinasi dua tahap <em>pretreatmen</em> untuk melihat efektivitas degradasi lignoselulosa dalam sampel. Tahap pertama dengan metode <em>hydrothermal pressure</em> pada suhu pemanasan uap 121 ^ºC dan tekanan 15-20 psi dengan variasi waktu proses selama 5; 15; 30; 45; dan 60 menit. Tahap kedua <em>pretreatment</em> dengan metode kimiawi menggunakan NaOH dengan variasi konsentrasi 0,5; 1; 1,5; 2; dan 2,5 M. Hasil penelitian menunjukkan 60 menit merupakan waktu optimum dari metode <em>hydrothermal pressure </em>pada sampel <em>Lemna minor</em> dengan kadar lignin 11,32 %, kadar selulosa 17,39 %, kadar hemiselulosa 16,73 % dan kadar gula total 0,82 %. Untuk tahapan <em>pretreatment</em> dengan pelarut alkali (NaOH) kandungan kadar lignin <em>Lemna minor</em> setelah <em>pretreatment</em> dengan NaOH 2,0 M sebesar 5,36 %, kadar. Kandungan kadar selulosa, hemiselulosa dan gula total optimum diperoleh pada konsentrasi 2,5 M dengan nilai kadar 31,03 %; 5,57 % dan 1,74 %. Efektivitas penurunan kadar lignin pada <em>pretreatment</em> <em>hydrothermal pressure</em> sebesar 37,04 % sedangkan <em>pretreatment</em> dengan NaOH sebesar 70,18 %. Kombinasi proses <em>pretreatment</em> memberikan hasil yang cukup baik terhadap proses degradasi lignin yang terkandung dalam sampel <em>Lemna minor </em>sehingga sangat efektif digunakan dalam proses pembuatan bioetanol dengan bahan dasar biomassa. </p><p>Bioethanol products with lignocellulosic biomass base ingredients have been developed as an alternative energy source. The main challenge in the production of lignocellulosic ethanol is on the pretreatment stage. Pretreatment is a stage that plays an important role in degrading lignocellulose into cellulose. In this study, we used a Lemna minor which is a water weed with a combination of two stages of pretreatmentt to see the effectiveness of lignocellulosic degradation in the sample. The first stage is hydrothermal pressure method of steam heating temperature 121 ^ºC and pressure 15-20 psi with variation of processing time for 5; 15; 30; 45; and 60 minutes. The second stage of pretreatment with chemical methods using NaOH with a concentration variation of 0.5; 1; 1.5; 2; and 2.5 M. The results showed that 60 minutes was the optimum time of the hydrothermal pressure method in the L.minor sample with the lignin level of 11.32 %, the cellulose 17.39 %, the hemicellulose 16.73 % and the total sugar 0.82 %. For the pretreatment stage with alkaline solvent (NaOH) the content of Lemna minor lignin after pretreatment with 2.0 M NaOH was 5.36 %. The content of cellulose, hemicellulose and total sugars was obtained at a concentration of 2.5 M with a grade value of 31.03 %; 5.57 % and 1.74 %. The effectiveness of lignin decrease in pretreatment hydrothermal pressure was 37.04 % while pretreatmentt with NaOH was 70.18 %. The combination of pretreatment process gives a good result to the lignin degradation process contained in the Lemna minor sample in order that it is very effective in the process of making bioethanol with biomass feedstock.</p>

PENGARUH PENGGUNAAN LARUTAN ALKALI DALAM UJI FOURIER TRANSFORM INFRARED PADA KOMPOSIT TERMOPLASTIK BERPENGISI SERBUK SERABUT KELAPA

Composite is a combination of two different materials to obtain a material with physical and mechanical properties are better than any of its constituent parts. One of the composite types which is much produced is composite with powdered natural fiber filler. This research uses the used polypropylene matrix and powdered coconut fiber as filler treated with Sodium Hydroxide (NaOH). The ratio of the matrix and the filler is 85:15. This ratio is the optimum value obtained by the composite tensile strength with ratio 100:0, 95:5, 90:10 and 85:15. The purpose of this study was to determine the effect of the use of an alkaline solution of the resulting composite properties especially towards lignin level, with Fourier Transform Infrared (FTIR) test on composite material used polypropylene with powdered coconut fiber as filler. The method used in the manufacture of composites is the method of extrusion. The matrix form of the used polypropylene mixed with coconut fiber powder that has been soaked with NaOH, then mixed in a container, then put into the extruder operating temperature 1750C, printed using a hot press at a temperature of 1750C, and cut into pieces appropriate testing. The results showed that the optimum processing occurs with NaOH for 2 days. The FTIR test result, showed that –OH cluster switch occured, be seen from the shifting of absortion band from 3417.04 cm-1 to 3476.84 cm-1 for the powdered coconut fiber and the shifting of absortion band from 3343.75 cm-1 to 3192.33 cm-1 for the composite, which is the –OH cluster of the lignin.