Abstract:

One of the outstanding challenges facing humankind is increasing crop production under various types of severe environmental conditions. Many measures have been taken to adopt molecular and biotechnological approaches that lead to the development of transgenic plants able to deal with such harsh and polluted environments. However, such solutions could be very expensive and require considerable efforts and time to achieve these objectives. The main objective of this review is to discuss the new biological solutions that have emerged in the last decade, as environmentally friendly approaches, perhaps to support and/or replace the present efforts. These solutions based on plant–microbe interactions could be a lifeline and promising alternative strategy to create plants with a high resistance to the extreme environments.

During the last two decades research projects have been conducted to study the ecology, identify the features, and the ecophysiology of native plants and the associated microorganisms in the Arabian Gulf region and particularly in Qatar. Many physiological and biochemical parameters have been determined, including organic solutes (amino acids like proline, glycinebetaine, soluble sugars, etc.), photosynthetic pigments, organic acids and inorganic ions especially heavy metals, along with the physical and chemical properties of the soil in various locations of the State of Qatar. Also, the microorganisms adjacent to and associated with these native plants were identified to elucidate the possible roles in the soil biota in supporting these plants against extreme environmental conditions.

Investigations of native plants in the Arabian Gulf states during the last decade have shown that wild plants exhibit different abilities to accumulate organic solutes to cope with the harsh natural environments. Pollution is a major factor stressing wildlife in this region due to the expansion of urban sectors and industrial activities of oil and gas. Compatible osmolytes, like proline, accumulate in wild plants in response to severe environmental conditions and heavy metal contaminated soil. Accumulation of these solutes in plant tissues could provide some level of adaptation and resistance against all these types of environmental stresses. We present some promising efforts in the Arabian Gulf region to remediate desert soil and water polluted with heavy metals and petroleum hydrocarbons. Substantial evidence is introduced about the roles of microorganisms associated with wild plants in natural habitats, such association may help them cope with the extreme stresses. Possible mechanisms adopted by microorganisms in alleviating the harsh abiotic stresses facing the wild life are discussed, one of which is the promotion of biosynthesis and transport of organic solutes to the plants. Also, the main possibilities of the origin of activities of the accumulation of compatible organic solutes are suggested and the objectives of the future research are discussed.

Key words: Arabian Gulf region, arid lands, compatible solutes, drought, microorganisms, modern approaches, pollution, salinity