DWI N. SUSILOWATI
Balai Besar Penelitian dan Pengembangan Bioteknologi dan Sumberdaya Genetik Pertanian, Jl. Tentara Pelajar No. 3A, Bogor 16111 Telp. (0251) 8337975

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Analisis Keragaman Genetik Isolat Bakteri Xanthomonas oryzae pv. oryzae dari Jawa Barat dan Jawa Tengah Berdasarkan Analisis ARDRA Gen 16SrRNA Suryadi, Yadi; Susilowati, Dwi N.; Lestari, Puji; Sutoro, Sutoro; Manzila, Ifa; Kadir, Trini Suryani; Albani, Sheryn Sunni; Artika, I Made
Jurnal Fitopatologi Indonesia Vol 10, No 2 (2014)
Publisher : Jurnal Fitopatologi Indonesia

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Abstract

Fifteen Xanthomonas oryzae pv. oryzae isolates from several regions in West Java and Central Java have been studied for their genetic diversity using amplified ribosomal DNA restriction analysis (ARDRA) 16SrRNA gene.Total of 13 ARDRA patterns from digestion of DNA with RsaI restriction enzyme was obtained, indicated higher genetic diversity of X. oryzae pv. oryzae. Phylogenetic analysis revealed a close genetic relationships among isolates. Isolates X. oryzae pv. oryzae 1/96pml and 61pml are closely related with isolates 29d, 59pml, and 60pml although they are isolated from different locations. The other closely related isolates were between X. oryzae pv. oryzae 5mgl with 23d, 38d, 10sbg, 8myd; while 6klt was close to 3ind and 2kr. The result of X. oryzae pv. oryzae genetic diversity can be used as a reference for strain or/isolates selection for development ofbacterial leaf blight resistance in Indonesia.  
Pengaruh Hormon Asam Indol Asetat yang Dihasilkan Azospirillum sp. terhadap Perkembangan Akar Padi Lestari, Puji; Susilowati, Dwi N.; Riyanti, Eny I.
Jurnal AgroBiogen Vol 3, No 2 (2007): Oktober
Publisher : Balai Besar Penelitian dan Pengembangan Bioteknologi dan Sumber Daya Genetik Pertanian

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Abstract

Free-living bacteria of thegenus Azospirillum live in close association with rice roots.This bacteria produced indole acetic acid (IAA), a plantgrowth hormon, to the environment. IAA was isolated fromcultures of Azospirillum strains and investigated for its effecton root development and plant height of rice variety IR64 invitro. Rice cultures of variety IR64 were grown in vitro andinoculated with cultures of Azospirilllum. Production of IAAby the bacterium during its growth period in rice culture mediumcontaining different levels of nitrogen was observed.Results of the experiment showed that strains AzospirillumAz15 and Az44 had a high ability to produce IAA, i.e., 57.93μg/ml at 12 days after incubation (DAI) and 40.42 μg/ml at 7DAI, respectively. The IAA production pattern of AzospirillumAz15 and Az44 in the liquid medium were fluctuativeuntil the end of the incubation period, while that of the strainAz7 was linier. Strain Az7 gave a better effect on the rootdevelopment and plant height than strains Az15 and Az44.Treatment combination of strain Az7 and 100% nitrogen gavehighest root development. High level of nitrogen increasedIAA content in the uninoculated culture, while low IAAcontent on the inoculated one. Inoculation the culture withstrain Az7 together with 50% nitrogen application resulted inthe IAA content, root dry weight, root length, fiber root number,and plant height as high as those on cultures containing100% nitrogen (1 mM NH4NO3) without inoculation. Inoculationof rice culture with Azospirillum is expected to reducenitrogen application on rice IR64 by the IAA production asindicated by significant changes in the root growth anddevelopment. A higher concentrations of IAA tend to givebetter effects on the root growth and development of riceIR64.
Increasing of N-uptake by Inoculation of Diazotroph Endophytic Bacteria in Vermiculite Media SUSILOWATI, DWI N.; SARASWATI, RATIH; HASTUTI, R.D; YUNIARTI, E.
Jurnal Tanah dan Iklim (Indonesian Soil and Climate Journal) No 26 (2007): Desember 2007
Publisher : Balai Besar Penelitian dan Pengembangan Sumberdaya Lahan Pertanian

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Abstract

Intensive selection of selected 15 isolates on N2-fixing activities and auxin production to diazotroph endophytic bacteria showed that five isolates were superior, that is KACP12 (0.2569 μmol hour-1 culture-1), KACP13 (0.3026 μmol hour-1 culture-1), KACP21 (0.4592 μmol hour-1 culture-1), KACP32 (0.3131 μmol hour-1 culture-1), and KAMG2 (0.4843 μmol hour-1 culture-1). Inoculated five superior isolates into soybean seeds in vermiculite media showed that soybean plant inoculated by KAMG2 has the highest nitrogenase specific activity compared to others and control, that is 2,54 ± 1,2 μmol hour-1 plant-1. However inoculation with KACM and KACP32 showed higher N-uptake of soybean plant. Although this research has conducted within theearly stage of soybean plant growth, it is obvious that inoculated diazotroph endophytic bacteria in vermiculite media seem to be a good method to introduce selected strain envisaging growth promoting and nitrogen fixation.
Growth Inhibition of Aspergillus spp. by Endophytic Bacteria Susilowati, Dwi N.; Haryono, Untung
Jurnal AgroBiogen Vol 14, No 1 (2018): June
Publisher : Balai Besar Penelitian dan Pengembangan Bioteknologi dan Sumber Daya Genetik Pertanian

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Aspergillus spp. (A. niger, A. flavus, and A. fumigatus) contaminate food commodities through production of secondary metabolites (mycotoxins) and aspergillosis, and thus pose severe hazard to human and animal health. Hence, the inhibition of mycotoxin-producing fungi on agricultural storage commodities needs to be considered. The aims of this study were to evaluate endophytic bacteria isolated from rice tissues that inhibit Aspergillus spp. growth, as well as to characterize the selected isolates morphologically and biochemically. Dual culture and disk diffusion method tests on 155 endophytic bacteria obtained three isolates, i.e. FB-Endo 65, FB-Endo 73, and FB-Endo 95, which showed inhibition zone from 13 to 17 mm against Aspergillus spp. growth. The inhibition zone and quantity of antifungal compounds increased positively with the length of incubation periods from 0 to 6 days. Antifungal compounds from the three isolates were insoluble in ethyl acetate, but soluble in methanol. The methanol soluble substance(s) from FB-Endo 73 showed higher inhibition zone than that of the other isolates. This result indicated that all three isolates produced strong antifungal activity. Morphological and biochemical identifications of the isolates revealed that all isolates belonged to the genus Bacillus sp. Further studies include identification and production methods of antifungal compounds of those endophytic bacteria and their application on stored seeds.
HUBUNGAN KARAKTER FENOTIPIK DAN HASIL BIJI PLASMA NUTFAH KACANG TUNGGAK [Vigna unguiculata (L.) Walp.] MENURUT ANALISIS LINTASAN Mastur, Mastur; Setyowati, Mamik; Susilowati, Dwi N.
BERITA BIOLOGI Vol 17, No 2 (2018)
Publisher : Research Center for Biology-Indonesian Institute of Sciences

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Abstract

Selection of high quality seedling through plant breeding activity can be conducted using yielded seeds, but usually it produces a low heritability. Therefore, this study was aimed to examine and analize several secondary phenotypic characters of 115 cowpea germ plasms in relation to seed yield. Relationship between secondary characters and seed yield was analyzed using path analysis. The result of path analysis showed that the number of cluster and the number of pod exhibited direct and significant effect to the seed yield of cowpea. Therefore, number of cluster and number of pod are necessary to be included as the selection criteria for breeding programme to produce high quality cowpea seedling with high yield.