Brown planthopper (BPH) is a phloem sap-sucking insect pest of rice which causes severe yield loss. We cloned the BPH18 gene from the BPH-resistant introgression line derived from the wild rice species Oryza australiensis. Map-based cloning and complementation test revealed that the BPH18 encodes CC-NBS-NBS-LRR protein. BPH18 has two NBS domains, unlike the typical NBS-LRR proteins. The BPH18 promoter::GUS transgenic plants exhibited strong GUS expression in the vascular bundles of the leaf sheath, especially in phloem cells where the BPH attacks. The BPH18 proteins were widely localized to the endo-membranes in a cell, including the endoplasmic reticulum, Golgi apparatus, trans-Golgi network, and prevacuolar compartments, suggesting that BPH18 may recognize the BPH invasion at endo-membranes in phloem cells. Whole genome sequencing of the near-isogenic lines (NILs), NIL-BPH18 and NIL-BPH26, revealed that BPH18 located at the same locus of BPH26. However, these two genes have remarkable sequence differences and the independent NILs showed differential BPH resistance with different expression patterns of plant defense-related genes, indicating that BPH18 and BPH26 are functionally different alleles. These findings would facilitate elucidation of the molecular mechanism of BPH resistance and the identified novel alleles to fast track breeding BPH resistant rice cultivars.

The Chenopodium genus comprises ~150 species, including Chenopodium quinoa and Chenopodium album, two important crops with high nutritional value. To elucidate the phylogenetic relationship between the two species, the complete chloroplast (cp) genomes of these species were obtained by next generation sequencing. We performed comparative analysis of the sequences and, using InDel markers, inferred phylogeny and genetic diversity of the Chenopodium genus. The cp genome is 152,099 bp (C. quinoa) and 152,167 bp (C. album) long. In total, 119 genes (78 protein-coding, 37 tRNA, and 4 rRNA) were identified. We found 14 (C. quinoa) and 15 (C. album) tandem repeats (TRs); 14 TRs were present in both species and C. album and C. quinoa each had one species-specific TR. The trnI-GAU intron sequences contained one (C. quinoa) or two (C. album) copies of TRs (66 bp); the InDel marker was designed based on the copy number variation in TRs. Using the InDel markers, we detected this variation in the TR copy number in four species, Chenopodium hybridum, Chenopodium pumilio, Chenopodium ficifolium, and Chenopodium koraiense, but not in Chenopodium glaucum. A comparison of coding and non-coding regions between C. quinoa and C. album revealed divergent sites. Nucleotide diversity >0.025 was found in 17 regions—14 were located in the large single copy region (LSC), one in the inverted repeats, and two in the small single copy region (SSC). A phylogenetic analysis based on 59 protein-coding genes from 25 taxa resolved Chenopodioideae monophyletic and sister to Betoideae. The complete plastid genome sequences and molecular markers based on divergence hotspot regions in the two Chenopodium taxa will help to resolve the phylogenetic relationships of Chenopodium.

SUMMARYAlthough susceptibility to seed shattering causes severe yield loss during cereal crop harvest, it is an adaptive trait for seed dispersal in wild plants. We previously identified a recessive shattering locus, sh-h, from the rice shattering mutant line Hsh that carries an enhanced abscission layer. Here, we further mapped sh-h to a 34-kb region on chromosome 7 by analyzing 240 F 2 plants and five F 3 lines from the cross between Hsh and Blue&Gundil. Hsh had a point mutation at the 3¢ splice site of the seventh intron within LOC_Os07g10690, causing a 15-bp deletion of its mRNA as a result of altered splicing. Two transferred DNA (T-DNA) insertion mutants and one point mutant exhibited the enhanced shattering phenotype, confirming that LOC_Os07g10690 is indeed the sh-h gene. RNA interference (RNAi) transgenic lines with suppressed expression of this gene exhibited greater shattering. This gene, which encodes a protein containing a conserved carboxy-terminal domain (CTD) phosphatase domain, was named Oryza sativa CTD phosphataselike 1 (OsCPL1). Subcellular localization and biochemical analysis revealed that the OsCPL1 protein is a nuclear phosphatase, a common characteristic of metazoan CTD phosphatases involved in cell differentiation. These results demonstrate that OsCPL1 represses differentiation of the abscission layer during panicle development.

Tocopherols, with antioxidant properties, are synthesized by photosynthetic organisms and play important roles in human and animal nutrition. In soybean, gamma-tocopherol, the biosynthetic precursor to alpha-tocopherol, is the predominant form found in the seed, whereas alpha-tocopherol is the most bioactive component. This suggests that the final step of the alpha-tocopherol biosynthetic pathway catalyzed by gamma-tocopherol methyltransferase (gamma-TMT) is limiting in soybean seed. Soybean oil is the major edible vegetable oil consumed, so manipulating the tocopherol biosynthetic pathway in soybean seed to convert tocopherols into more active alpha-tocopherol form could have significant health benefits. In order to increase the soybean seed alpha-tocopherol content, the gamma-TMT gene isolated from Perilla frutescens was overexpressed in soybean using a seed-specific promoter. One transgenic plant was recovered and the progeny was analyzed for two generations. Our results demonstrated that the seed-specific expression of the P. frutescens gamma-TMT gene resulted in a 10.4-fold increase in the alpha-tocopherol content and a 14.9-fold increase in the beta-tocopherol content in T2 seed. Given the relative contributions of different tocopherols to vitamin E activity, the activity in T2 seed was calculated to be 4.8-fold higher than in wild-type seed. In addition, the data obtained on lipid peroxidation indicates that alpha-tocopherol may have a role in preventing oxidative damage to lipid components during seed storage and seed germination. The increase in the alpha-tocopherol content in the soybean seed could have a potential to significantly increase the dietary intake of vitamin E.

No abstract