| ?.Genetic Analysis and Mapping of noe1-2 Gene involved in lesion-like in RiceRice is the staple food as nearly half of the world's population.Therefore,it is more important to high and stable yield of rice.Lesion-like symptoms of rice leaf often accompany with increasing disease resistance.Therefore,to explore the genetic mechanism and regulatory pathways of rice leaf lesion,that is very important to improve rice disease resistance.In this study,a leaf lesion material noe1-2 was screened from the mutant library of Yixiang 1B mutant induced by EMS.The studied performed phenotypic characteristics,histological structure,chloroplast ultrastructure,disease resistance response,genetic analysis and gene mapping.The main results are as follows:1.The phenotype observation of rice mutant noe1-2 showed that plant height dwarfing,tiller number,1000-grain weight,grain number per panicle and grain number per panicle were significantly lower than those of wild type.2.Histological observation showed that the vascular bundle sheaths involved in the intercellular plasmodesmata in the mutant leaves were disordered,and found that phloem which transported nutrients atrophied was decreased,and thicker-walled cell layers which participated in nutrient transport in the branchlets were decreased.To compared with wild type,the number of chloroplasts in the mutant decreased significantly,and a large number of starch grains were accumulated in the mesophyll cells using transmission electron microscopy(TEM).The soluble starch synthase SSI,soluble starch synthase SSIIb,amylase branching enzyme BEIIa,starch transporter regulators OsSEX1 and sucrose transporter SUT2,SUT4 decreased in the mutant leaves by qPCR.Thus,the results suggest that mutation of gene involved in lesion-like may affect starch synthesis and sucrose transporter.3.The resistance of mutant noe1-2 to MoPot 2 was relatively stronger than that of wild-type by inoculating rice blast strains at trifoliate stage.The result suggests that the mutation of noe1-2 stimulates immune response.4.Genetic analysis showed that the mutation of noe1-2 was controlled by a single recessive gene.The mutant gene was located on chromosome 3 by BSA method.The molecular marker was between RM7576 and Os3-34.8 of 88.2 kb,and the physical distance was about 88.2 kb.Because the location interval is too large,MutMap technology is further used for fine mapping of candidate genes.MutMap sequencing analysis showed that a candidate gene Os03g0131200 with a sense mutation in the coding region and a SNP index of 1 was found in the preliminary localization region.Sequence comparison revealed that the mutant noe1-2 had a single base mutation from C to T in the fourth exon of the candidate gene,which resulted in the mutation of propionic amino acid into threonine amino acid.Os03g0131200 encodes catalase(OsCATC or NOE 1),which has been cloned and mutated to produce phenotypes similar to those of mutant noe1-2.However,some new phenotypes such as starch granule enrichment in the above-mentioned leaves have been identified.Therefore,the gene identified in this study is very likely to be a new allele of Noe 1,named noe1-2.Functional validation of candidate genes is under way.5.The expression of NOE1 gene was affected by ABA hormone.Therefore,we determined the hormone content in the leaves of mutant noe1-2.The results showed that the contents of ABA,GA and IAA in the leaves of mutant noe1-2 increased,while BR and CTK did not change significantly in wild type and mutant.II.Quality Analysis of Colored RiceRice is mainly divided into red rice,black rice and white rice.Compared with white rice,black rice and red rice have rich nutritional functions,such as flavonoids and polyphenols,as well as trace elements several times higher than ordinary rice.With the improvement of people's living standard,the requirement of nutritional quality and physiological efficacy of rice is getting higher and higher.We selected eight representative rice varieties and measured their mineral elements,polyphenols,proteins,starch and antioxidant capacity.It was found that although the content of protein and amylose in colored rice was similar to that in white rice,the content of minerals in colored rice was higher than that in white rice,and the content of polyphenols in colored rice was much higher than that in white rice.In addition,black rice and red rice have stronger antioxidant capacity than white rice,among which red rice is the strongest among three different color rice varieties.Next,the correlations between metal elements,metal elements and polyphenols,polyphenols and antioxidant capacity are analyzed.The results are as follows:1.The results of correlation analysis of six mineral contents show that there is a negative correlation between Ca and Fe,Zn and Cu,a positive correlation between Cu and Zn,Mg and Mn,Fe,and no correlation between other mineral elements.It shows that Mg can promote the absorption of Fe and Mn,while Zn can promote the absorption of Cu.2.The correlation analysis between polyphenols and mineral elements,K and P shows that the content of polyphenols is positively correlated with mineral content,indicating that polyphenols contribute to the absorption of trace elements;but there is almost no correlation between polyphenols and K and P,indicating that polyphenols do not affect the absorption of P and K,leading to the difference between P and K mainly due to the difference of genetic background.3.The correlation analysis between polyphenols,antioxidant capacity,protein and amylose showed that polyphenols contributed to antioxidant capacity;the correlation between amylose and protein was low,indicating that the content of starch did not affect protein synthesis;there was almost no correlation between polyphenols and protein and starch,indicating that polyphenols did not affect starch and egg.White matter accumulation;correlation analysis between polyphenols and antioxidant capacity showed that polyphenols contributed to the enhancement of antioxidant capacity. |
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