Abstract Different species of Trichoderma harzianum have been used mainly as an antagonist against a number of plant diseases. There is a direct relationship between the biocontrol potential of these fungi and the rate of enzymatic degradation of the cell walls of pathogens. Following the successful production of chimeric chit 42 via protein engineering in the previous work of authors, the resulting recombinant protein was transferred to T. harzianum. In this study presence and stability of chimeric Chitinase (Chit42-ChBD) was verified then growth stimulating and biocontrol potential of the six improved isolates were evaluated on bean plants under laboratory and greenhouse conditions compared to the wild type. Among engineered isolates, Chit42-ChBD3 with 53.83% growth inhibition on Rhizoctonia showed the highest growth rate and sporulation compared to the wild type in the dual culture test. The results showed that ChBD15 and ChBD13 had better performance in terms of increasing nutrient uptake and root growth thereby enhancing the growth rate and yield performance of the whole plant compared to the plants treated with wild type and non-T. harzianum treated plants.

Fusarium oxysporum é um fitopatógeno amplamente difundido nos solos. A doença amarela do grão-de-bico (Cicer arietinum), causada por ele é destrutiva e um grande problema nas regiões produtoras do Irã. Três métodos de laboratório: amplificação aleatória de DNA genômico (RAPD), coloração de atividade enzimática e determinação das dimensões de colônia, foram usados para diferenciar isolados de Fusarium oxysporum altamente virulentos (HV) e fracamente virulentos (WV). Baseado no tamanho da colônia (método morfológico tradicional) e na capacidade dos isolados produzirem enzimas pécticas, cinco isolados HV foram diferenciados de três WV. Enquanto os isolados HV formaram colônias grandes (entre 10,1 e 12,6 mm de diâmetro) e apresentaram o mesmo padrão enzimático, os isolados WV produziram colônias pequenas (entre 5,8 e 7,8 mm de diâmetro) e não tiveram atividade enzimática detectável no gel de cobertura corado. Doze primers arbitrários foram testados nos 8 isolados de Fusarium oxysporum por reação de polimerase em cadeia (PCR). As análises dos dados da amplificação de DNA pelo método de amplificação aleatória do DNA polimórfico (RAPD) diferenciaram os isolados HV dos WV. Os resultados obtidos pelo teste RAPD confirmaram a classificação dos 8 isolados pelos testes de patogenicidade, tamanho da colônia e atividade enzimática de coloração nos dois grupos, HV e WV.

Fusarium oxysporum is a common soilborn plant pathogen with a worldwide distribution. Fusarium yellows disease of chickpea (Cicer arientinum) caused by F.oxysporum is one of the most destructive soilborn disease which is a major production constraint in chickpea-growing regions of Iran. Three laboratory methods "amplification of genomic DNA using random primers, enzyme activity staining, and colony size determination" have been used to discriminate between highly virulent (HV) and weakly virulent (WV) isolates of F. oxysporum. On the basis of colony size (a traditional morphological method) and the ability of isolates to produce pectic enzymes, five HV isolates were differentiated from three WV isolates. The HV isolates formed large colony (ranging from 10.1 to 12.6 mm in diameter) and showed the same enzyme pattern,while the WV isolates produced small colony (ranging from 5.8 to 7.8 mm in diameter) and had not detectable enzyme activity in the stained overlaying gel. Twelve arbitrary 10-mer primers were tested on these 8 isolates of F. oxysporum by Polymerase Chain Reaction (PCR). Cluster analysis of the data from the DNA amplification by Random Amplified Polymorphic DNA (RAPD), differentiated HV from WV isolates. The results obtained from RAPD test confirmed the classification of these eight isolates based on pathogenicity test, colony size, and enzyme activity staining into two groups (HV and WV).