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Isoprenoids, a large kind of plant natural products, are synthesized by the mevalonate (MVA) pathway in the cytoplasm and the 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway in plastids. As one of the rate-limiting enzymes in the MVA pathway of soybean (Glycine max), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) is encoded by eight isogenes (GmHMGR1–GmHMGR8). To begin, we used lovastatin (LOV), a specific inhibitor of GmHMGR, to investigate their role in soybean development. To further investigate, we overexpressed the GmHMGR4 and GmHMGR6 genes in Arabidopsis thaliana. The growth of soybean seedlings, especially the development of lateral roots, was inhibited after LOV treatment, accompanied by a decrease in sterols content and GmHMGR gene expression. After the overexpression of GmHMGR4 and GmHMGR6 in A. thaliana, the primary root length was higher than the wild type, and total sterol and squalene contents were significantly increased. In addition, we detected a significant increase in the product tocopherol from the MEP pathway. These results further support the fact that GmHMGR1–GmHMGR8 play a key role in soybean development and isoprenoid biosynthesis. [ABSTRACT FROM AUTHOR]

As a class of water-soluble, fructose-based oligo- and polysaccharides, fructans are major nonstructural carbohydrates and an important carbon source for grain filling in wheat (Triticum aestivum L.). Four enzymes are involved in fructan synthesis in higher plants, and 6-SFT is a key enzyme in fructan biosynthesis. In this study, thirteen single nucleotide polymorphisms were detected in 6-SFT-A2 in 24 wheat accessions, forming three haplotypes. Two cleaved amplified polymorphic sequence markers developed based on polymorphisms at sites 1870(A-G) and 1951(A-G) distinguished the three haplotypes. 6-SFT-A2 was located on chromosome 4A, between markers P2454.3 and P3465.1 in a doubled haploid (DH) population derived from the cross Hanxuan 10 × Lumai 14. The DH population comprising 150 lines and a historical population consisting of 154 accessions were used in a 6-SFT-A2 marker–trait association analysis. The three haplotypes were significantly associated with thousand-grain weight (TGW) under rainfed conditions. HapIII had a significant positive effect on TGW. There were significant differences between the Hanxuan 10 and Lumai 14 genotypes in both rainfed and irrigated environments. The average TGW of Lumai 14 (HapIII) was higher than that of Hanxuan 10 (HapI). The frequencies of 6-SFT-A2HapIII in cultivars released at different periods showed that it had been strongly positively selected in breeding programs. The preferred HapIII for TGW occurred at higher frequencies in Gansu, Beijing, Shanxi, and Hebei than other regions in northern China. [ABSTRACT FROM AUTHOR]