Disease resistance in transgenic plants has been improved, for the first time, by the insertion of a gene from a biocontrol fungus. The gene encoding a strongly antifungal endochitinase from the mycoparasitic fungus Trichoderma harzianum was transferred to tobacco and potato. High expression levels of the fungal gene were obtained in different plant tissues, which had no visible effect on plant growth and development. Substantial differences in endochitinase activity were detected among transformants. Selected transgenic lines were highly tolerant or completely resistant to the foliar pathogens Alternaria alternata , A. solani , Botrytis cinerea , and the soilborne pathogen Rhizoctonia solani . The high level and the broad spectrum of resistance obtained with a single chitinase gene from Trichoderma overcome the limited efficacy of transgenic expression in plants of chitinase genes from plants and bacteria. These results demonstrate a rich source of genes from biocontrol fungi that can be used to control diseases in plants.

Intensive agriculture is a farming system characterised by a large use of inputs, causing a large pressure on the environment. As peculiar and efficient example of intensive agriculture cultivation under plastic tunnels provides several advantages for farmers due to improvement of microclimatic conditions coupled with a relatively low investment costs. In the Mediterranean Basin such cultivation systems reach about 200,000 ha mainly in Spain, Turkey, Italy, and Morocco. As downside, intensive agriculture negatively affects soil fertility principally because of a loss in soil organic matter. Sustainable practices providing organic amendments could be a useful tool to maintain or increase organic matter content in agricultural soils, preserving and improving soil fertility. An improved knowledge of management factors affecting soil quality is crucial to plan farming systems that effectively maintain soil fertility. Therefore, this review focuses on the potential value of organic amendments in the recovery of soil fertility, in particular in sites under plastic cover intensive farming system. Following a brief overview of the effects of intensive agriculture on soil, the review describes various organic amendments used in agriculture and their benefits on soil fertility, to conclude with the need, in the future researches, to identify organic amendments able to maximize a recovery of soil fertility.

No abstract

No abstract