Wx 和PAL6对高直链淀粉含量稻米抗性淀粉的遗传调控

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Abstract：The fat and amylose content of rice play a regulatory role in the biosynthesis of resistant starch subtype5（RS5），which is the form of theRS in cooked rice.Investigating the genetic effects of the Waxy （ （Wx） ） gene，which regulates amylose biosynthesis，and the PAL6 gene involved in the fat synthesis，on different RS subtypes，as well as the relationship between rice quality and RS，is valuable for molecular breeding and quality improvement of rice with high RS.In this study，69 rice germplasms with varying amylose contents were evaluated forRS content in cooked rice（RSc），RS content in retrograded rice （RSr），and cooking and eating quality traits. Functional variants of Wx and PAL6 were identified to assess their genetic effects and haplotype functions on RSc and RSr.Results indicated that both Wx and PAL6 significantly influence RS biosynthesis in rice，although the efect of PAL6 was comparatively less.The RS content were significantly higher （ （P<0.01 ）in Wxa and Wx–T genotypes compared to Wλxb and Wx–C genotypes，while RSr and RSb（RSr-RSc） levels were significantlyhigher（ P<0.05 or P<0.01 ）inPAL6-2 typethan in PAL6–I type.Haplotype analysisrevealed that Hap1 （ Wxa-Wx-T-PAL6-I） ，Hap2（ Wxa -Wx-T-PAL6-2），and Hap3（Wxα-Wx-C-PAL6-2） significantly increased RSc and RSr. Significant positive correlation （P<0.01 ）were observed between RSc and RSr on apparent amylosecontent，hot paste viscosity，cold paste viscosity，setback value，and consistence value.In contrast， significant negative correlations （ P<0.05 or P<0.01 ）were found with gel consistency，breakdown value， pasting temperature，and peak viscosity. RSr was also negatively correlated with crude fat content，indicating that combination of fat and amylose during rice cooking might inhibit short-term retrogradation，thereby affecting RSr formation.Among the high RS haplotype germplasm，six with superior quality，CG133R， GBC120，GBC116，RILC-20，Shuhui 885 and RILC-15，were identified. This study revealed novel haplotypes asociated with high RS content in rice，providing a theoretical foundation and germplasm resources for molecular breeding and quality improvement of rice with high RS.

Keywords：rice;resistantstarch;amylose; Wx ;PAL6

水稻（OryzasativaL.）作为三大粮食作物之一，全球约有 50% 的人口以稻米为主食，是人体碳水化合物和卡路里摄入的主要来源[1]。（剩余17254字）