Identification and characterization of genomic regions on chromosomes 4 and 8 that control the rate of photosynthesis in rice leaves

Abstract

DNA marker-assisted selection appears to be a promising strategy for improving rates of leaf photosynthesis in rice. The rate of leaf photosynthesis was significantly higher in a high-yielding indica variety, Habataki, than in the most popular Japanese variety, Koshihikari, at the full heading stage as a result of the higher level of leaf nitrogen at the same rate of application of nitrogen and the higher stomatal conductance even when the respective levels of leaf nitrogen were the same. The higher leaf nitrogen content of Habataki was caused by the greater accumulation of nitrogen by plants. The higher stomatal conductance of Habataki was caused by the higher hydraulic conductance. Using progeny populations and selected lines derived from a cross between Koshihikari and Habataki, it was possible to identify the genomic regions responsible for the rate of photosynthesis within a 2.1 Mb region between RM17459 and RM17552 and within a 1.2 Mb region between RM6999 and RM22529 on the long arm of chromosome 4 and on the short arm of chromosome 8, respectively. The designated region on chromosome 4 of Habataki was responsible for both the increase in the nitrogen content of leaves and hydraulic conductance in the plant by increasing the root surface area. The designated region on chromosome 8 of Habataki was responsible for the increase in hydraulic conductance by increasing the root hydraulic conductivity. The results suggest that it may be possible to improve photosynthesis in rice leaves by marker-assisted selection that focuses on these regions of chromosomes 4 and 8.

Detection of QTL for exudation rate at ripening stage in rice and its contribution to hydraulic conductance

“…We conclude from these results that the genomic region including qEXR1 affects root length, and this explains the increase in root surface area and thereby enhancing hydraulic conductance. A Habataki allele on chromosome 4 enhanced hydraulic conductance in the Sasanishiki [29] and Koshihikari [21] genetic backgrounds. However, no rice QTL for enhancing hydraulic conductance on chromosome 2 has hitherto been reported.…”

“…Especially, Akenohoshi increases a root mass relating to root surface area and hydraulic conductance after the panicle formation stage compared with the Japanese commercial cultivars and its root mass and hydraulic conductance becomes large remarkably at the ripening stage [7]. By contrast, the stomatal conductance of Japanese commercial cultivars with low hydraulic conductance is suppressed even under small vapor pressure deficit in the morning [16,20,21]. These data promise the detection of QTLs for enhancing hydraulic conductance which is one of the most complex factors affecting photosynthetic rate.…”

Leaf Photosynthesis and Its Genetic Improvement from the Perspective of Energy Flow and CO2Diffusion

“…Therefore, to use these resources for breeding, we should elucidate the physiological factors that determine the observed varietal differences in P n and identify the QTLs that control them (Flood et al, 2011). This section presents the physiological and genetic bases underlying the variation in P n found in some rice lines that have been examined by Adachi et al (2011aAdachi et al ( , 2011bAdachi et al ( , 2011cAdachi et al ( , 2013 and Taylaran et al (2011) and the prospects for future improvement of rice photosynthesis.…”

“…We have just begun QTL analysis using populations derived from a cross between Koshihikari and Takanari. Genetic analysis of populations derived from a cross between Koshihikari and the indica cultivar Habataki, which shows comparable P n to Takanari, allowed the mapping four QTL regions associated with P n on chromosomes 4, 5, 8 and 11 (Adachi et al, 2011a(Adachi et al, , 2011b. The Habataki segments of chromosome 5 and 11 were found to be responsible for increasing LNC, that of chromosome 8 for increasing g s and that of chromosome 4 for both traits.…”

Caracterização fisiológica de diferentes genótipos de arroz de terras altas

“…A priorização da seleção de plantas com maior EUA nos processos de melhoramento genético pode levar, muito provavelmente, às reduções de produtividade (BLUM, 2009 (YOSHIDA, 1975;DINGKUHN, 1991;JODO, 1995;HIRAYAMA;WADA;NEMOTO, 2006;CENTRITO et al, 2009;ADACHI et al, 2011;KUSUMI et al, 2012;GU et al, 2012 …”