Denitrification within the genus Azospirillum and other associative bacteria

2001 ◽  
Vol 28 (9) ◽  
pp. 991 ◽  
Author(s):  
Karin Kloos ◽  
Alexander Mergel ◽  
Christopher Rösch ◽  
Hermann Bothe
Keyword(s):  
Nitrite Reductase ◽  
Plant Growth Promoting Rhizobacteria ◽  
Selective Advantage ◽  
Molecular Data ◽  
Associative Bacteria ◽  
Activity Measurements ◽  
Plant Growth Promoting ◽  
Cytochrome Cd1 ◽  
Polymerase Chain ◽  
Dissimilatory Nitrite Reductase

This paper originates from an address at the 8th International Symposium on Nitrogen Fixation with Non-Legumes, Sydney, NSW, December 2000 Different Azospirillumstrains and some other plant growth-promoting rhizobacteria (PGPR) were screened for the occurrence of genes coding for denitrification and nitrogenase reductase (nifH) using polymerase chain reaction (PCR)-based techniques. All PGPR examined were nitrogenase-positive. Azospirillum strains were remarkably dissimilar with respect to denitrification capabilities, in particular with respect to genes of the dissimilatory nitrite reductase. A. brasilense, A. lipoferum and A. halopraeferens strains possess a cytochrome cd1-containing nitrite reductase with low sequence similarities among them. A. irakense and A. doebereinerae have a Cu-containing nitrite reductase and A. amazonense is unable to denitrify. The molecular data were corroborated by activity measurements. The current results indicate that the inability to perform denitrification is unlikely a selective advantage for Azospirillum spp. and other associative bacteria for forming an association with plant roots.

Arabidopsis thaliana: a model for studies of colonization by non-pathogenic and plant-growth-promoting rhizobacteria

2001 ◽  
Vol 28 (9) ◽  
pp. 975
Author(s):  
Kenneth J. O'Callaghan ◽  
Richard A. Dixon ◽  
Edward C. Cocking
Keyword(s):  
Arabidopsis Thaliana ◽  
Plant Growth ◽  
Stress Responses ◽  
Plant Defence ◽  
Plant Growth Promoting Rhizobacteria ◽  
Molecular Data ◽  
Flavonoid Metabolism ◽  
Plant Growth Promoting ◽  
Plant Genes ◽  
Growth Promoting

This paper originates from an address at the 8th International Symposium on Nitrogen Fixation with Non-Legumes, Sydney, NSW, December 2000 Arabidopsis thaliana L. has many features favoring its use as a model in studies of plant-growth-promoting rhizobacteria (PGPR), such as diazotrophs. Several niches are colonized in the root system of Arabidopsis, including xylem, and intact colonized roots can be observed microscopically without sectioning of tissues. Studies of plant genes involved in colonization are facilitated by the ease with which plants are transformed and by the availability of mutant lines and other accessions obtainable from stock centers. Lines of Arabidopsis carrying reporter gene fusions are helping to reveal the pattern of expression of previously cloned plant genes induced by rhizobacteria. Studies utilizing indole-3-acetic acid (IAA)-producing PGPR and Arabidopsis that contain an auxin-responsive GUS fusion suggest that plants perceive IAA released by bacteria in the rhizosphere. The role of flavonoids in the colonization of non-legumes is being assessed using transgenic Arabidopsis with altered flavonoid metabolism and using tt mutants, which lack functional versions of specific genes for flavonoid metabolism. Studies of plant defence and of stress responses are producing molecular data on plant genes induced by inoculation of Arabidopsis roots with non-pathogens.

Aplikasi Bacillus subtilis pada beberapa Bahan Organik terhadap Pertumbuhan dan Produksi Tanaman Cabai Rawit (Capsicum frutescens L.)

2020 ◽  
Vol 21 (1) ◽  
pp. 14-19
Author(s):  
Praptiningsih Gamawati Adinurani ◽  
Sri Rahayu ◽  
Nurul Fima Zahroh
Keyword(s):  
Bacillus Subtilis ◽  
Plant Growth ◽  
Plant Growth Promoting Rhizobacteria ◽  
Capsicum Frutescens ◽  
Plant Growth Promoting ◽  
Growth Promoting

Mikroba Bacillus subtilis merupakan agen pengendali hayati mempunyai kelebihan sebagai Plant Growth Promoting Rhizobacteria (PGPR) yaitu dapat berfungsi sebagai biofertilizer, biostimulan, biodekomposer dan bioprotektan. Tujuan penelitian mengetahui potensi B. subtilis dalam merombak bahan organik sebagai usaha meningkatkan ketersediaan bahan organik tanah yang semakin menurun. Penelitian menggunakan Rancangan Petak Terbagi dengan berbagai  bahan organik sebagai petak utama (B0 = tanpa bahan organik, B1 = kotoran ayam,  B2 = kotoran kambing, B3 = kotoran sapi) dan aplikasi B.subtilis sebagai anak petak (A0 = 0 cc/L, A1 = 5cc/L, A2 = 10 cc/L, Pengamatan meliputi variabel tinggi tanaman, indeks luas daun, jumlah buah per tanaman, berat buah per tanaman, dan bahan organik tanah. Data pengamatan  dianalisis ragam  menggunakan  Statistical Product and Service Solutions (SPSS) versi 25 dan dilanjutkan dengan uji Duncan untuk mengetahui signifikansi perbedaan antar perlakuan. Hasil penelitian menunjukkan tidak terdapat interaksi antara bahan organik kotoran ternak dan konsentrasi B. subtilis terhadap semua variabel pengamatan. Potensi B. subtilis sangat baik dalam mendekomposisi bahan organik yang ditunjukkan dengan peningkatan bahan organik, dan hasil terbaik pada kotoran  sapi (B3) dan konsentrasi B. subtilis 15 mL/L masing-masing sebesar 46.47 % dan 34.76 %. Variabel pertumbuhan tidak berbeda nyata kecuali tinggi tanaman dengan pertambahan tinggi paling banyak pada pemberian kotoran kambing sebesar 170.69 %.

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