# Fungi of the _Trichoderma_ Genus: Future Perspectives of Benefits in Sustainable Agriculture
## 5 Application of _Trichoderma_ Fungi in Promoting Plant Growth
### Salinity  
[PERSON] et al. [19] noted that 5% NaCl inhibited the growth of _T. hamatum_, _T. polysporum_, and _T. saturisporum_ by more than 96%. In contrast, a 5% saline solution had no effect on the development of mycelium of _T. harzianum_, _T. lwingii_, and _T. viride_. According to [PERSON] et al. [203], _T. reseei_ resisted NaCl concentrations below 200 mM, whereas at 250 mM, there was a 50% reduction in dry and fresh mycelium mass. [PERSON] et al. [189] documented that _T. asperellum_, _T. hamatum_, _T. harzianum_, and _T. viride_ showed high tolerance to the presence of sodium chloride in a medium. The above-mentioned authors reported that a concentration of 600 uM reduced sporulation but did not decrease mycelium, while a solution of 1000 uM NaCl completely inhibited mycelium growth. [PERSON] et al. [204] proved that the salinity level of the medium affected the ability of _T. atroviride_ to become simultaneously mycoparasitic as well as stimulate the growth of cucumber plants. According to [PERSON] et al. [204], the non-volatile metabolites produced in vitro by _Trichoderma_ sp. more strongly limited the growth of _F. oxysporum_ mycelium after the use of the medium in which the concentration of NaCl was 100 mM than when it was 0 mM. Volatile metabolites inhibited pathogen development by 50% and 58%, respectively, in conditions of the absence of salt in the medium and under salt stress. The results of observations in the greenhouse showed that the disease index of cucumber root rot was 43.125% at 0 mM sodium chloride concentration and 55% at 100 mM sodium chloride concentration. The researchers also analyzed the effect of _Trichoderma_ sp. on cucumber growth at 100 mM and 200 mM NaCl medium. The fungi increased the length, fresh and dry root and shoot mass, and chlorophyll a and b concentration in cucumber plants at 100 mM NaCl medium to a greater extent than at 200 mM. The enhancement in total chlorophyll content was 13.93% and 19.68%, respectively, for 100 mM and 200 mM salt concentrations. Similarly, [PERSON] et al. [205] documented that as the NaCl content of the medium increased, the ability of _T. longibrachiatum_ to limit the growth of _F. pseudograminearum_ improved. The average rate of pathogen inhibition was 33.86% for the control, 36.32% for 50 mM NaCl, 44.59% for 100 mM NaCl, and 46.62% for 150 mM NaCl. In addition, it was reported that saline concentration influenced the growth parameters of wheat in different ways. The greatest enhancement in fresh and dry root weight and relative water content occurred at 150 mM sodium chloride concentration. [PERSON] et al. [206] found that _T. longibrachiatum_ increased root length and wheat height by 4.16 cm and 4.20 cm, respectively, and chlorophyll content by 0.53 mg/g compared to salt stress conditions. The authors reported that the treatment of seeds with the analyzed fungi resulted in the enhancement of fresh and dry root and shoot weight, proline content, soluble sugars and proteins, and expression of genes encoding antioxidant enzymes in wheat. In contrast, a study by [PERSON] et al. [137] showed that the biomass, root length, and shoot length of maize inoculated with _T. asperellum, T. aureoviride, T. harzianum, and T. koningiopsis_ decreased as the medium salinity increased. In addition, the average chlorophyll concentration decreased from 2.75 mg/g to 1.02 mg/g, with NaCl concentrations of 1.67 dS/m and 52 dS/m, respectively. According to [PERSON] et al. [165] too high a content of NaCl salt in the soil reduces its microbiological activity, porosity, and aeration and interferes with the conduction of minerals and water. Salinity stress induces ionic and osmotic stress in the plant, which leads to the production of reactive oxygen forms (ROS), destroying biomolecules [20] and lipid peroxidation, thus damaging the cytoplasmic membranes of plant cells. Long-term accumulation of a large amount of salt reduces the activity of enzymes responsible for chlorophyll biosynthesis.