Screening and Physiological Characterization of Rice Rhizosphere Bacteria from Coastal Soil that Produce Indol Acetic Acid in Saline Condition

Climate change due to global warming increase water sea levels. Increasing the frequency of rising sea levels to the mainland can cause salinity problems for agricultural land in coastal areas. It will affect on plant productivity. Planting varieties of crops tolerant to salinity is one of the solutions to overcome this problem. Application of indigenous Plant Growth Promoting Rhizobacteria (PGPR) are expected to further increase the tolerancy of crops to salinity. This study was conducted to select a number of rhizobacteria isolates from rice field which were tolerant to saline conditions and capable of producing phytohormonesauxin (IAA). A total of 48 rhizobacteria isolates from coastal rice field of Patimban (Ptb) and Eretan (Er), West Java have been analyzed. Among 48 isolates, 12 selected isolates produced IAA>30 ppm. Isolate Er B1.3 and Er B1.7a have ability to grow on minimal salt medium content with 15% NaCl. Both isolates is still capable of producing IAA with consecutive concentrations at 1,55 ppm and 3,1 ppm on minimal medium salt content with 10% NaCl. IaaM gene identification results prove that isolates Er B1.3 and Er B1.7a producing IAA through the IAM pathway. Based on 16S rRNA sequencing results known isolates Er B1.3 and Er B1.7a are closely related to Brevibacterium sp. and Aeromonas sp., respectively

Growth Inhibition of Aspergillus Spp. by Endophytic Bacteria

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

Analisis Aktivitas Nitrogenase dan Gen Nifh Isolat Bakteri Rhizosfer Tanaman Padi dari Lahan Sawah Pesisir Jawa Barat

Penambatan nitrogen oleh bakteri rhizosfer dapat dimanfaatkan untuk menyiasati dampak salinitas pada tanah sawah pesisir. Kemampuan tersebut disebabkan oleh aktivitas nitrogenase yang disandikan gen nifH pada komponen II. Penelitian ini bertujuan menganalisis aktivitas nitrogenase pada kondisi salin dan mengidentifikasi gen nifH. Sebanyak 50 isolat bakteri rhizosfer asal tanah sawah pesisir daerah Eretan dan Patimban, Jawa Barat telah dianalisis. Lima isolat yang menunjukkan aktivitas nitrogenase pada kondisi salin adalah Er B1 3, Er B1 4, Er B1 9, Er B2 10, dan Ptb B1 4. Gen nifH kelima sampel diidentifikasi menggunakan PCR menghasilkan amplikon berukuran ~360 bp. Aktivitas nitrogenase tertinggi berdasarkan Analisis Reduksi Asetilen (ARA) diperoleh pada isolat Er B2 10 yang memiliki kekerabatan terdekat dengan bakteri Providencia sp. Hasil yang diperoleh membuktikan bahwa beberapa bakteri asal sawah pesisir dapat menambat nitrogen pada kondisi salin

Rhizosphere Microbial Genetic Resources as PGPR Potential Isolated from Maize Inbred Populations Var.Bisma

A number of rhizosphere bacteria affect plant growth through contributing to the host plant-source of endogenous phytohormones. This study aims to obtain potential microbial genetic resources which isolated from corn. A total of 24 potential microbial genetic resource collections were isolated from the rhizosphere population of inbred corn plant var. Bisma obtained from the Biogen-Plant GeneBank collection. The potential of microbial genetic resources observed include the ability to produce IAA, N2 fixation, Phosphate solubility, and their ability to stimulate corn seed germination. Rhizosphere bacteria were isolated using the soil extract media. Isolates that showed the ability to produce IAA, N2 fixation and high phosphate solubility were tested for corn seed germination. The results showed that there were 24 isolates obtained from corn rhizosphere which dominated by bacilliform-shaped gram-positive bacteria capable of IAA producing ranged from 4.83 to 125.84 ppm. Almost 16 rhizosphere bacterial isolates were capable of dissolving phosphate with the phosphate solubility index ranged from 2.1 to 4.6. The selected potential isolates of J11, J16 and J19 were able to stimulate the corn seed germination

Identifikasi 26 Isolat Bakteri Endofitik Dan Filosfer Padi Dengan Analisis Sekuen16s Rdna [Identification of 26 Endophytic and Phyllosphere Bacteria Isolated From Rice by 16s Rdna Sequence Analyses]

The research was subjected to identify 26 endophytic and phyllosphere bacteria isolated from 4 rice varieties using sequencing method of 16S rDNA.The sequences were then aligned with reference sequence from Gen-Bank data library by BLAST program from NCBI to find the most related identity of the isolates analysed.The sequencing analysis revealed that some isolates have a high identity to Staphylococcus and Serratia (5 isolates each), Bacillus (4 isolates), Microbacteria (3 isolates), Pseudomonas (2isolates) and Klebsiella, Acidovorak, Bulkholderiaceae, Agrobacterium and Shewanella (1 isolate each). No specific isolate dominated in both endophytic and phyllosphere group, nor host-specific isolate found in the four rice varieties

The Potential of Nutmeg’s Microbes (Myristica fragrans Houtt.) as Antagonistic Agents against Rigidoporus microporus

This study aimed to obtain yeast and bacteria from Myristica fragrans Houtt., which have the potential to produce chitinase enzymes with antagonistic ability against Rigidoporus microporous. Both microorganisms were extracted from the leaves and fruit of nutmeg. A total of 35 yeast and 29 bacterial isolates were obtained, with different morphological characters. The chitinolytic test was carried out qualitatively, and the parameters observed include the clear zones around the colony. A total of 4 bacterial isolates produced chitinase enzymes (BP 1.2.1, BP 2.1.1, EPBj II.K1, and EPBj II. K2) with a chitinolytic index of 3.92, 5.38, 2.00, and 1.66, respectively. Yeast isolates were negative for chitinase enzymes. The difference in index value indicated a variation in enzyme activity. The antagonist test was carried out using a dual culture method. A total of 1 yeast and 14 bacterial isolates inhibited the growth of R. microporous, and each has a different inhibitory zone. Based on the percentage of inhibition value, the highest percentage occurred in P.K1(41.1%), P. K2 (50%), dan EPBj II. K6 (42.2%). The antagonist test indicator includes the formation of inhibitory zones on the medium. Hemolysis test showed that yeast and bacteria are not able to break down blood cells in the medium. The molecular identification showed that P. K1 and P. K2 isolates were classified as Bacillus subtillis and EPBj II. K6 were identified as Bacillus aerius with 100% sequence homology and 99% bootstrap value respectively. These findings provided information about potential microbes that control white root fungus.      

Growth Inhibition of Aspergillus spp. by Endophytic Bacteria

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

Iodine Salt Consumption in Indonesian Households: Baseline Health Survey 2007

Background: Iodine Deficiency Disorder (100) reduction program has been implemented since 1976. According to the National Economic Survey 2002, the average consumption of iodized salt was 6. 26 grams. The results of Iodine Salt Survey (SGY) 2003 showed that the consumption of iodine salt at the household level was 73.2%, meanwhile, the baseline health survey (Riskesdas) 2007 showed there was reduction of iodine salt consumption towards 60.2%. Methods: Type of study was secondary data analysis with cross-sectional design utilizing the Riskesdas 2007's data. Sample was selected purposively according to the previous SGY's survey based on the endemically criteria namely highly endemic, mediocre and non endemic. Results: The results of the analysis were there was discrepancy of iodine salt consumption among urban and rural areas as well as mother's education level. The iodine salt consumption was higher in the urban area (65.5%) compare to the rural area (52.9%). The higher the education of mothers the better the iodine salt consumed. The USAge of iodine salt in the households based on salt quick test was 60.2%, meanwhile, according to the salt titration it was only 23.4%. The results of Excretion Iodine Urine showed that the iodine intake among the school children (age of 6-12 years old) was 12.8% and was still below the cut-off point prevalence, which is greater than 50%. The conclusion of this analysisis that there was evidence of iodine salt reduction consumed at the household level. Conversely, there was inclination of the percentage of iodine urine level among the school children in Indonesia in the year 2007. It is recommended that policy analysis need to be conducted due to the achievement of the Universal Salt iodization target, especially in the endemic areas to asses the existence of the IDO prevalence