Haloalkaliphilic Fungi and Their Roles in the Treatment of Saline-Alkali Soil

The saline-alkali soils mainly affected by excess soda are significantly harmful to most crops and soil organisms. In the community structure of saline-alkali soil, the lack of fungal species diversity remains the most prominent problem; thus supplement of the haloalkaliphilic fungi, a unique group of extremophiles that can grow optimally under conditions of extreme salinity and alkalinity, is the preferred method for the treatment of saline-alkali field. The haloalkaliphilic fungi possess several mechanisms to alleviate the damage of salt and alkali. These fungi are capable of absorbing salt ions, producing organic acids, and providing macromolecules such as cellulose degradation enzymes and other biomasses that are beneficial for soil physical properties, fertility, activity, and even health. Some haloalkaliphilic fungi express high resistance to a variety of stressors and the ability to degrade crop straw; so they are genetic tools that can be used to identify and validate genes involved in abiotic stress resistance and cellulose decomposition genes. This chapter focuses on the following aspects: isolation and characterizations of extreme haloalkaliphilic fungi, molecular mechanisms for saline-alkali soil mycoremediation, and application of haloalkaliphilic fungi in saline-alkali soil mycoremediation.