Effect of one or more microorganisms on the yield components of upland rice under greenhouse conditions.

The use of beneficial microorganisms is an important strategy to improve rice production in a sustainable way. The study was carried out to determine the effect of single and combined beneficial microorganism on the development of upland rice. The experiment was performed in greenhouse and arranged in a completely randomized design with 29 treatments and 4 replications. Treatments consisted of rice seeds cultivar BRS A501 CL treated with single and combined multifunctional microorganisms (1 (Serratia marcescens), 2 (Bacillus toyonensis), 3 (Phanerochaete australis), 4 (Trichoderma koningiopsis), 5 (Azospirillum brasilense), 6 (Azospirillum sp.), 7 (Bacillus sp.), 8 to 28 (combination of all these microorganisms in pairs) and 29 (control)). Inoculation of upland rice with sole and combined microorganism on upland rice increased the roots and shoots development, yield components and grain yield of upland rice. The combinations of Bacillus sp. (BRM 63573) and A. brasilense (AbV5), Azospirillum sp. (BRM 63574) + B. toyonensis (BRM 32110) and Phanerochaete australis (BRM 62389) + Serratia marcenscens (BRM 32114) led to improved roots and shoots development; increased number of panicles and grains per pot, 1000 grains weight and grain yield of rice plants. Besides, the combinations allow helped in increased accumulation of nutrients in roots, shoots and grains of rice plants.

Molecular and morphological characterization of rice phylloplane fungi and determination of the antagonistic activity against rice pathogens.

Cladosporium spp. is a cosmopolitan fungal genus. In the literature, it has been reported as a biological agent for controlling several plant diseases, but its mechanism of action has never been clarified. The present study aims to identify Cladosporium spp. based on the DNA phylogeny of nine isolates obtained from the phylloplane of rice and their potential antagonistic activity against the main fungal pathogens that affect rice crop. Nine isolates of Cladosporium spp. were identified based on DNA phylogeny, molecular and morphological characterization, and their antagonistic effects with the rice pathogens C. miyabeanus, M. oryzae, M. albescens and S. oryzae. Four isolates were selected to study lytic enzymes such as ß-1,3-glucanase, chitinase and protease, and only one isolate was selected for a conidial germination and appressoria formation assay. The nine isolates were identified as C. cladosporioides, C. tenuissimum and C. subuliforme. Four isolates, identified as C. cladosporioides, inhibited the mycelial growth of rice pathogens such as C1H (68.59%) of S. oryzae, C5 G (74.32%) of C. miyabeanus, C11 G (75.97%) of M. oryzae and C24 G (77.39%) of M. albescens. C24 G showed a high activity of lytic enzymes, was tested against C. miyabeanus and M. oryzae, and inhibited conidial germination and appressorium formation by more than 59.36%. The characterization of C. cladosporioides suggested this species as a potential bioagent for the management of several rice diseases, especially rice blast. This is the first time that a potential biological agent from the genus Cladosporium identified at the species level was isolated from the rice phylloplane, and some of its mechanisms of action were demonstrated, such as increasing lytic enzyme activity against rice pathogens.