Using chromosome introgression lines to map quantitative trait loci for photosynthesis parameters in rice (Oryza sativa L.) leaves under drought and well-watered field conditions

Abstract

Photosynthesis is fundamental to biomass production, but sensitive to drought. To understand the genetics of leaf photosynthesis, especially under drought, upland rice cv. Haogelao, lowland rice cv. Shennong265, and 94 of their introgression lines (ILs) were studied at flowering and grain filling under drought and well-watered field conditions. Gas exchange and chlorophyll fluorescence measurements were conducted to evaluate eight photosynthetic traits. Since these traits are very sensitive to fluctuations in microclimate during measurements under field conditions, observations were adjusted for microclimatic differences through both a statistical covariant model and a physiological approach. Both approaches identified leaf-to-air vapour pressure difference as the variable influencing the traits most. Using the simple sequence repeat (SSR) linkage map for the IL population, 1–3 quantitative trait loci (QTLs) were detected per trait–stage–treatment combination, which explained between 7.0% and 30.4% of the phenotypic variance of each trait. The clustered QTLs near marker RM410 (the interval from 57.3 cM to 68.4 cM on chromosome 9) were consistent over both development stages and both drought and well-watered conditions. This QTL consistency was verified by a greenhouse experiment under a controlled environment. The alleles from the upland rice at this interval had positive effects on net photosynthetic rate, stomatal conductance, transpiration rate, quantum yield of photosystem II (PSII), and the maximum efficiency of light-adapted open PSII. However, the allele of another main QTL from upland rice was associated with increased drought sensitivity of photosynthesis. These results could potentially be used in breeding programmes through marker-assisted selection to improve drought tolerance and photosynthesis simultaneously.

Association mapping for photosynthesis and yield traits under two moisture conditions and their drought indices in winter bread wheat (Triticum aestivum L.) using SSR markers

“…Because of the primary importance of photosynthesis in crop growth, identifying QTLs linked with photosynthesis is an important step in efficient MAS for improved yield (Gu et al, 2011). This assertion is further supported by growing evidence regarding the existence of genetic variation for photosynthesis rates in the available germplasm and that yield progress in cereals is associated with improved photosynthesis (Fischer and Edmeades, 2010).…”

QTL for chlorophyll fluorescence of barley plants grown at low oxygen concentration in hydroponics to simulate waterlogging

“…Tolerant plants seem to be able to maintain or conserve energy, but also escape mechanisms are common (Hattori et al 2009;van Veen et al 2013). Chlorophyll fluorescence is widely accepted as an indicator of the activity of PSII, which is involved in electron transport in plant photosynthesis and is particularly sensitive to stresses (Fracheboud et al 2004;Guo et al 2008;Gu et al 2012). Various fluorescence parameters have been found to be closely correlated with carbon assimilation under different stresses in rice (Guo et al 2008), lucerne (Smethurst and Shabala 2003), soybean (Yin et al 2010), wheat ) and maize (Fracheboud et al 2004), as well as grain yield in barley (Bertholdsson 2013) and, under optimal conditions intriticale (Hura et al 2009).…”

“…Various fluorescence parameters have been found to be closely correlated with carbon assimilation under different stresses in rice (Guo et al 2008), lucerne (Smethurst and Shabala 2003), soybean (Yin et al 2010), wheat ) and maize (Fracheboud et al 2004), as well as grain yield in barley (Bertholdsson 2013) and, under optimal conditions intriticale (Hura et al 2009). Fluorescence parameters has also been used for mapping QTL in relation to drought stress in wheat (Czyczyło-Mysza et al 2011), rice (Gu et al 2012) and barley (Guo et al 2008;Wójcik-Jagla et al 2013), salt tolerance in barley (Aminfar et al 2011) and biomass and yield in wheat (Czyczylo-Mysza et al 2013). However, to our knowledge there have been no previous efforts to associate chlorophyll fluorescence with WLT, besides research by Pang et al (2004) and Bertholdsson (2013), who used it to characterise WLT of barley cultivars.…”

Drought-tolerance QTLs commonly detected in two sets of reciprocal introgression lines in rice

“…The use of quantitative trait locus (QTL) mapping has contributed to a better understanding of the genetic basis of DT-related traits. An increasing number of QTLs related to drought response have been reported, and these include QTLs for osmotic adjustment (Robin et al 2003), grain yield and yield components (Lanceras et al 2004;Xu et al 2005;Wang et al 2013), stay-green (Jiang et al 2004), canopy temperature, leaf rolling and leaf drying (Yue et al 2005), carbon isotope discrimination (D 13 C) (Takai et al 2009;Xu et al 2009), photosynthesis parameters (Gu et al 2012), and root morphology and other root-related traits such as root penetration ability (Price et al 2002a;Babu et al 2003). The earlier approach to improve grain yield under reproductive-stage drought stress through selection based on secondary traits such as root architecture, leaf water potential, panicle water potential, osmotic adjustment, relative water content, etc.…”

“…However, very few QTLs are actively targeted in breeding programs because most QTLs have not been validated in different genetic backgrounds and environments (Price et al 2002b;Yue et al 2008), which may also have hampered the pace of DT breeding. Nevertheless, several major DT QTLs, such as qDTY 12.1 (Bernier et al 2007;Mishra et al 2013), qDTY 1.1 (Vikram et al 2011), qDTY 6.1 (Venuprasad et al 2012), and the QTL closely associated with the markers EM11-11 ) and RM410 (Gu et al 2012) have been identified and used for developing DT varieties via MAS. Through functional and comparative genomic studies, many stressresponsive transcription factors were recently shown to affect DT (Liu et al 2007;Lu et al 2009;Ye et al2009;Zhao et al 2010;Jeong et al 2013).…”