2005 ◽  
Vol 18 (5) ◽  
pp. 385-396 ◽  
Author(s):  
Yanqing Wang ◽  
Yumiko Ohara ◽  
Hitoshi Nakayashiki ◽  
Yukio Tosa ◽  
Shigeyuki Mayama

Pseudomonasz fluorescens FPT9601-T5 was originally identified as an endophytic plant growth-promoting rhizobacteria (PGPR) on tomato. To perform a molecular dissecttion of physiological and biochemical changes occurring in the host triggered by P. fluorescens FPT9601-T5 colonization, the model plant Arabidopsis was used in this study. Root colonization of Arabidopsis with P. fluorescens FPT9601-T5 promoted plant growth later than three weeks after inoculation and partially suppressed disease symptoms caused by Pseudomonas syringae pv. tomato DC3000, indicating that P. fluorescens FPT9601-T5 acted as a PGPR on Arabidopsis. To obtain a global view on transcript modification during the Arabidopsis-FPT9601-T5 interaction, we performed microarray analysis using Affymetrix Genechip probe arrays representing approximately 22,800 genes. The results showed that 95 and 105 genes were up- or down-regulated, respectively, more than twofold in FPT9601-T5-treated Arabidopsis plants as compared with control plants. Those up-regulated included genes involved in metabolism, signal transduction, and stress response. Noteworthy, upon FPT9601-T5 colonization, putative auxin-regulated genes and nodulin-like genes were up-regulated, and some ethylene-responsive genes were down-regulated. Our results suggest that P.fluorescens FPT9601-T5 triggered plant responses in a manner similar to known PGPR and, at least in some aspects, to rhizobia.


2020 ◽  
Author(s):  
Anastasiia Fetsiukh ◽  
Julian Conrad ◽  
Jonas Bergquist ◽  
Fantaye Ayele ◽  
Salme Timmusk

ABSTRACTIn coming decades drought is expected to expand globally owing to increased evaporation and reduced rainfall. In order to reduce the vulnerability of agricultural systems we need to understand the crop plant growth environment. Understanding, predicting and controlling the rhizosphere has potential to harness plant microbe interactions, improve plant responses to environmental stress and mitigate effects of climate change. Our plant growth-promoting rhizobacteria (PGPR) are isolated from the natural laboratory ‘Evolution Canyon’ Israel (EC). The endophytic rhizobacteria from the wild progenitors of cereals have been co-habituated with their hosts for long periods of time. The study revealed that silica particles (SN) triggered the PGPR production of exopolysaccharides (EPS) containing D-glucuronate (D-GA). This leads to increased plant biomass accumulation in drought-stressed growth environments. The PGPR increased EPS content increases the water holding capacity (WHC) and osmotic pressure of the biofilm matrix. Light- and electron-microscopic studies show that in the presence of SN particles, bacterial morphology is changed, indicating that SNs are associated with significant reprogramming in bacteria.The results here show that the production of EPS containing D-GA is induced by SN treatment. The findings encourage formulation of cells considering microencapsulation with materials that ensure higher WHC and hyperosmolarity under field conditions. Our results illustrate the importance of considering natural soil nanoparticles in the application of PGPR. Osmotic pressure involvement of holobiont cohabitation is discussed.


2020 ◽  
Vol 21 (1) ◽  
pp. 14-19
Author(s):  
Praptiningsih Gamawati Adinurani ◽  
Sri Rahayu ◽  
Nurul Fima Zahroh

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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