A REVIEW OF MOLECULAR MARKERS TO GENES INVOLVED IN MINERAL NUTRITION EFFICIENCY CONTROL IN RICE (Oryza sativa L.)

Abstract

A b s t r a c tTo date, the doses of mineral fertilizers per hectare in Asia and Europe are the highest in the world. This leads to serious problems for environment contamination, including water pollution, an increase in emission of hotbed gases and a decrease of pH in soils and water. Nitrogen utilization in rice, wheat and corn is 26-30 %, and in vegetables less than 20 % (K. Vinod et al., 2012). During last fifty years high yielding varieties are being bred at high mineral nutrition. An increase in doses of fertilizers has resulted in smaller efficiency of their application and an increasing adverse impact on the environment. As a rule, the varieties which are high productive due to introduced high doses of fertilizers are less effective in their utilization. Besides, productivity of such varieties is very unstable as being considerably influenced by doses of the introduced fertilizers, terms of their introduction, ambient temperature, etc. In the paper we briefly reviewed the mechanisms of plants adaptation to low nitrogen and phosphorus nutrition, and the genotypic distinctions in the efficiency of using these elements. The efficiency is noted to be influenced no only by various responses of genotypes to the applied doses, but also by a source of element and the interactions between a genotype and the environment. Comparison of genotypes of rice has shown 20-fold distinction in efficiency of phosphorus use between extreme types (M. Wissuwa et al., 2001). All highly effective genotypes are cultivars with age-old longevity or endemics. Most P-containing organic compounds that plants have to extract from soil should be turned into the accessible form by phosphatases. So a genotypic diversity in the efficiency of phosphorus use is related to different activity of phosphatases. Phytin acid produced by roots and the rhizosphere microorganisms is one of the agents promoting phosphorus accessibility (A.E. Richardson et al., 2001). Therefore, the plant ability to support favorable microbial communities in the rhizosphere serves as the additional adaptive mechanism. Plant adaptation to low nitrogen and phosphorus levels can be due to root system development, intensification of absorption and utilization, and also to biosynthesis and excretion of the organic acids to increase availability of the mineral elements in the rhizosphere (H. Lambers et al., 2006). Redistribution of the absorbed elements between generative and vegetative organs, between leaves on one or different stems stands for an internal efficiency of nutrient utilization. Variability on the efficiency of nutrition utilization among 30 rice genotypes resulted mainly from distinctions in the growth of root system which increased the absorbing area. Variability of genotypes on the tolerance to a lack of phosphorus was mainly due to different ability to P absorption, while the changes in the efficiency of P utilization were insignificant. OTL related to N and P utilization and specific molecular markers flanking the loci, RM 53, RM 25, RM 600, RM 242, RM 23...