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.

ABSTRACT GeneXpert is one of the recent technological instruments used to diagnose tuberculosis in a short span of time. In this study, the performance of GeneXpert MTB/RIF assay for the diagnosis of extrapulmonary tuberculosis (EPTB) was compared with light-emitting diode Fluorescent Microscopy (LED-FM) in Khyber Pakhtunkhwa, Pakistan. A total of 737 EPTB samples were collected from tuberculosis (TB) suspected patients. Out of these samples, male to female ratio was 53% (n = 390) to 47% (n = 347) respectively. The sensitivity and specificity was 73% and 100% for GeneXpert, while 40% and 100% for LED-FM microscopy. This shows that the sensitivity of GeneXpert is 40–50%, higher than LED-FM microscopy. GeneXpert also detected low number of bacilli as compared to LED-FM microscopy.

Abstract Agricultural crops suffer many diseases, including fungal and bacterial infections, causing significant yield losses. The identification and characterisation of pathogenesis-related protein genes, such as chitinases, can lead to reduction in pathogen growth, thereby increasing tolerance against fungal pathogens. In the present study, the chitinase I gene was isolated from the genomic DNA of Barley (Hordeum vulgare L.) cultivar, Haider-93. The isolated DNA was used as template for the amplification of the ∼935 bp full-length chitinase I gene. Based on the sequence of the amplified gene fragment, class I barley chitinase shares 93% amino acid sequence homology with class II wheat chitinase. Interestingly, barley class I chitinase and class II chitinase do not share sequence homology. Furthermore, the amplified fragment was expressed in Escherichia coli Rosetta strain under the control of T7 promoter in pET 30a vector. Recombinant chitinase protein of 35 kDa exhibited highest expression at 0.5 mM concentration of IPTG. Expressed recombinant protein of 35 kDa was purified to homogeneity with affinity chromatography. Following purification, a Western blot assay for recombinant chitinase protein measuring 35 kDa was developed with His-tag specific antibodies. The purified recombinant chitinase protein was demonstrated to inhibit significantly the important phytopathogenic fungi Alternaria solani, Fusarium spp, Rhizoctonia solani and Verticillium dahliae compared to the control at concentrations of 80 µg and 200 µg.

A emergência e o estabelecimento do estande em sementes de pimentão (Capsicum annus L.) e de tomate (Lycopersicon lycopersicum (L.) (Karsten ex Farw) são freqüentemente lentos e desuniformes, principalmente sob condições de estresse. Experimentos de campo às vezes não têm fornecido resposta ao condicionamento em sementes de pimentão. Este trabalho estudou os efeitos combinados de matricondicionamento e aplicação de giberelina na germinação e estande de sementes de pimentão e tomate. Sementes de pimentão e de tomate foram condicionadas com um sólido matricial, Micro Cel E, na presença e ausência do ácido gilberélico, por um, dois, três e quatro dias, a 15 e 25ºC. Os resultados demonstram que, em todos os casos, os tratamentos combinados com a aplicação de ácido giberélico foram eficientes em melhorar a germinação e a emergência de sementes de pimentão e de tomate. O tempo para germinação sofreu redução, em média, de dois a três dias, nas sementes matricondicionadas. Assim, o matricondicionamento, durante o qual é suspenso o início do processo de germinação, proporcionou o único meio para que as enzimas induzidas pela aplicação de ácido gilberélico digerissem eficientemente as células do endosperma e reduzissem as barreiras mecânicas, fornecendo, assim, ao embrião, energia para seu desenvolvimento.

Emergence and stand establishment of tomato (Lycopersicon lycopersicum (L.) (Karsten ex Farw) and pepper (Capsicum annus L.) seeds are often slow and erratic, particularly under stress conditions. Field emergence trials sometimes have not responded to priming in pepper. This study examined the combined effects of matriconditioning and gibberellin application on the germination and stand establishment of pepper and tomato seeds. Pepper and tomato seeds were conditioned with a solid carrier, Micro Cel E, in the presence of gibberellic acid (GA) for 1, 2 , 3 and 4 days at 15 and 25ºC. The results showed that, in all cases, even under stress conditions, the combination of matriconditioning with GA was effective in improving germination and emergence of pepper and tomato. The germination time was, in average, reduced by 2 to 3 days by primed seeds. Thus, matriconditioning, during which germination is suspended, provides an unique means to rapidly and efficiently digest the endosperm by GA-induced enzymes and reduce the mechanical restraints of endosperm thus providing energy to start and sustain embryo growth.