Mapping of QTLs associated with cytosolic glutamine synthetase and NADH‐glutamate synthase in rice ( Oryza sativa L.)

Abstract

Ninety-eight backcross inbred lines (BC1F6) developed between Nipponbare, a japonica rice, and Kasalath, an indica rice were employed to detect putative quantitative trait loci (QTLs) associated with the contents of cytosolic glutamine synthetase (GS1; EC 6.3.1.2) and NADH-glutamate synthase (NADH-GOGAT; EC 1.4.1.14) in leaves. Immunoblotting analyses showed transgressive segregations toward lower or greater contents of these enzyme proteins in these backcross inbred lines. Seven chromosomal QTL regions for GS1 protein content and six for NADH-GOGAT protein content were detected. Some of these QTLs were located in QTL regions for various biochemical and physiological traits affected by nitrogen recycling. These findings suggested that the variation in GS1 and NADH-GOGAT protein contents in this population is related to the changes in the rate of nitrogen recycling from senescing organs to developing organs, leading to changes in these physiological traits. Furthermore, a structural gene for GS1 was mapped between two RFLP markers, C560 and C1408, on chromosome 2 and co-located in the QTL region for one-spikelet weight. A QTL region for NADH-GOGAT protein content was detected at the position mapped for the NADH-GOGAT structural gene on chromosome 1. A QTL region for soluble protein content in developing leaves was also detected in this region. Although fine mapping is required to identify individual genes in the future, QTL analysis could be a useful post-genomic tool to study the gene functions for regulation of nitrogen recycling in rice.

Transgenic Approaches to Engineer Nitrogen Metabolism

“…The co-localization of GS1 genes with QTLs for yield (Hirel et al 2001;Obara et al 2001) supports this strategy.…”

“…In addition, GS1 is expressed in photosynthetic cells of conifers, where GS2 is absent , and also in angiosperms during physiological differentiation of plastids (Gallardo et al 1988;Gálvez et al 1990) or under stressful situations such as water deficiency (Bauer et al 1997) or pathogen attack (Pérez-García et al 1998). Recent genetic and molecular approaches have shown that GS may be a key component of plant nitrogen use efficiency and yield (Hirel et al 2001;Obara et al 2001). All these recent reports suggest that cytosolic GS (GS1) plays a central and pivotal role in nitrogen metabolism that is essential for nitrogen-use-efficiency in higher plants.…”

Leaf nitrogen remobilisation for plant development and grain filling

“…QTLs for NUE have been mapped in a number of plant species, including maize, rice, and Arabidopsis (Hirel et al. 2001; Obara et al. 2001; Loudet et al.…”

Advances in Research on Fertilization Management of Vegetable Crops

“…To date, QTLs for NUE in vegetable species are beginning to be available (Chan-Navarrete et al 2015). QTL analysis for NUE, with particular regard to the metabolic processes linked to nitrogen assimilation, identified several loci that co-segregate with GS1 and NADH-GOGAT (Obara et al 2001). QTL analysis for genes involved in the development and architecture of the root system can also provide useful information for improving the efficiency of plant mineral uptake.…”