Characterization and survival of broad-spectrum biocontrol agents against phytopathogenic fungi / Caracterización y supervivencia de agentes de control biológico de amplio espectro frente a hongos fitopatógenos

Resumen Este estudio tuvo como objetivo aislar, caracterizar e identificar bacterias de control biológico que poseen actividad antifúngica de amplio espectro de la filosfera de diferentes cultivos, incluidos el maíz, el trigo y la papa, así como evaluar su actividad en la promoción del crecimiento. En este estudio, 14/113 bacterias de control biológico mostraron actividad antifúngica. Los aislamientos bacterianos M11 y M33 (de maíz), del total de 113, fueron reseleccionados debido a su fuerte actividad antifúngica de amplio espectro (más del 50%) después de su evaluación contra cuatro hongos fitopatógenos que afectan cultivos de alta importancia económica, entre ellos, Alternaría alternata, Rhizoctonia solani, Fusarium oxysporum y Fusarium verticillioides. Los aislamientos se evaluaron, adicionalmente, para determinar los rasgos que promueven el crecimiento de las plantas, es decir, producción de ácido indolacético, solubilización de fosfato, producción de celulasa, compuestos orgánicos volátiles microbianos, cianuro de hidrógeno y sideróforos. Las 14 cepas aisladas mostraron resultados positivos para la producción de la hormona ácido indolacético y la enzima celulasa; 10 cepas fueron positivas para la producción de cianuro de hidrógeno. Además, se observó producción de sideróforos en el caso de 7 cepas, mientras que 5 pudieron solubilizar fosfato inorgánico. Los compuestos orgánicos volátiles microbianos solo fueron sintetizados por los aislamientos M11 y M33, que fueron identificados como Bacillus amyloliquefaciens y Bacillus subtilis, respectivamente, mediante secuenciación del gen ARNr 16S. El estudio de supervivencia mostró que las bacterias de control biológico, es decir, B. amyloliquefaciens y B. subtilis, tienen la capacidad de sobrevivir sobre un sustrato a base de melasa, por un período de tres meses.

Characterization and survival of broad-spectrum biocontrol agents against phytopathogenic fungi.

The current study intended to isolate, characterize and identify biocontrol bacteria possessing broad-spectrum antifungal activity from the phyllosphere of different crops including maize, wheat and potato and to assess their growth-promoting activity. In this study 14/113 biocontrol bacteria showed antifungal activity. Bacterial isolates M11 and M33 from maize out of 113 were re-selected on the basis of their strong (more than 50%) broad spectrum antifungal activity after their assessment against four economically important phytopathogenic fungi including Alternaria alternata, Rhizoctonia solani, Fusarium oxysporum and Fusarium verticillioides. The isolates were further assessed for plant growth promoting traits, i.e., indole-3-acetic acid production, phosphate solubilization, production of cellulase, microbial volatile compounds, hydrogen cyanide and siderophores. All fourteen isolates showed positive results for the production of indole-3-acetic acid hormone and cellulase enzyme, 10 isolates were positive for hydrogen cyanide production; siderophores production was observed in 7 isolates while 5 isolates showed ability to solubilize inorganic phosphate. Microbial volatile compounds were only synthesized by M11 and M33, which were identified as Bacillus amyloliquefaciens and Bacillus subtilis respectively by 16S rRNA gene sequencing. The survival study revealed that biocontrol bacteria B. amyloliquefaciens and B. subtilis have the ability to survive in cost effective molasses containing carrier material up to a three-month period.

Exploring threatened traditional knowledge; ethnomedicinal studies of rare endemic flora from Lesser Himalayan region of Pakistan

ABSTRACT Himalayas are one among the world biodiversity hotspots harboring many endemic medicinal plants. Despite augmentation in the documentation of ethnopharmacological knowledge of medicinal plant species, information regarding endemic species is still underway. Current paper highlights the traditional medicinal uses of rare endemic and unexplored group of plants having potential for novel chemical constituents with effective pharmacological activities. In total, 142 informants (91 male and 51 female) including seventeen traditional healers were interviewed using semi-structured questionnaire, personal observations and group discussions. Interviews were taken in field or otherwise photographs were shown for identification. Females were interviewed indirectly through male family members. For data analysis, quantitative analytical approach was adopted using ethnopharmacological indices as Relative frequency of citations and Fidelity Level. In total, 38 endemic plant species belonging to nineteen families were utilized by the local inhabitants. Highest number of endemics was belonging to Ranunculaceae (7), followed by Gentianaceae and Rosaceae (4 each) with respect to number of species. Highest number of endemics was used in fever, wound healing, throat infection and tonic (4 species each). Root was the most widely used part (36.17%) in cure of diseases and the leading mode administered was decoction (25.49%). Highest use reports and RFC values were recorded for Pimpinella stewartii (58 citations, 0.41 RFC), Caltha alba var. alba (52 citations, 0.37 RFC). Endemic plant species considerably contribute toward ethnomedicinal knowledge and despite rarity, the communities prefer their utilization. Conservation of endemics is necessary for future availability to the local communities.