A genome-wide association study (GWAS) can be a powerful tool for the identification of genes associated with agronomic traits in crop species, but it is often hindered by population structure and the large extent of linkage disequilibrium. In this study, we identified agronomically important genes in rice using GWAS based on whole-genome sequencing, followed by the screening of candidate genes based on the estimated effect of nucleotide polymorphisms. Using this approach, we identified four new genes associated with agronomic traits. Some genes were undetectable by standard SNP analysis, but we detected them using gene-based association analysis. This study provides fundamental insights relevant to the rapid identification of genes associated with agronomic traits using GWAS and will accelerate future efforts aimed at crop improvement.

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Fibroblast proliferation and migration play important roles in wound healing. bFGF is known to promote both fibroblast proliferation and migration during the process of wound healing. However, the signal transduction of bFGF-induced fibroblast migration is still unclear, because bFGF can affect both proliferation and migration. Herein, we investigated the effect of bFGF on fibroblast migration regardless of its effect on fibroblast proliferation. We noticed involvement of the small GTPases of the Rho family, PI3-kinase, and JNK. bFGF activated RhoA, Rac1, PI3-kinase, and JNK in cultured fibroblasts. Inhibition of RhoA did not block bFGF-induced fibroblast migration, whereas inhibition of Rac1, PI3-kinase, or JNK blocked the fibroblast migration significantly. PI3-kinase-inhibited cells down-regulated the activities of Rac1 and JNK, and Rac1-inhibited cells down-regulated JNK activity, suggesting that PI3-kinase is upstream of Rac1 and that JNK is downstream of Rac1. Thus, we concluded that PI3-kinase, Rac1, and JNK were essential for bFGF-induced fibroblast migration, which is a novel pathway of bFGF-induced cell migration.

Lodging has been a major roadblock to attaining increased crop productivity. In an attempt to understand the mechanism for culm strength in rice, we isolated an effective quantitative trait locus (QTL), STRONG CULM3 (SCM3), the causal gene of which is identical to rice TEOSINTE BRANCHED1 (OsTB1), a gene previously reported to positively control strigolactone (SL) signaling. A near-isogenic line (NIL) carrying SCM3 showed enhanced culm strength and increased spikelet number despite the expected decrease in tiller number, indicating that SL also has a positive role in enhancing culm strength and spikelet number. We produced a pyramiding line carrying SCM3 and SCM2, another QTL encoding APO1 involved in panicle development. The NIL-SCM2+SCM3 showed a much stronger culm than NIL-SCM2 and NIL-SCM3 and an increased spikelet number caused by the additive effect of these QTLs. We discuss the importance of utilizing suitable alleles of these STRONG CULM QTLs without inducing detrimental traits for breeding.

SignificanceRice architecture is an important agronomic trait for determining yield; however, the complexity of this trait makes it difficult to elucidate the molecular mechanisms. This study applied a strategy of using principal components (PCs) as dependent variables for a genome-wide association study (GWAS). SPINDLY was identified to regulate rice architecture by suppressing gibberellin (GA) signaling. Further study using GA-signaling mutants confirmed that levels of GA responsiveness regulate rice architecture, suggesting that the utilization of a favorable SPINDLY allele will improve crop productivity. The strategy presented in this study of performing GWAS using PC scores will provide valuable information for plant genetics and will improve our understanding of complex traits at the molecular level.

Microvascular tissue transfer has become an indispensable procedure for head and neck reconstruction. Although remarkable progress has been made technically, anastomosed vessel occlusion is still a serious complication. Even with technically skilled microsurgeons, anastomosed vessel occlusion occurs because the technique is not the sole prophylaxis against thrombosis in microsurgery. Therefore, to minimize the possibility of an unfavorable result in microsurgery, microsurgeons must be familiar with management options for a vascular compromised flap. Most investigators have agreed that venous obstruction occurs more often than arterial obstruction. Here, we reviewed the published literature on the salvage of venous compromised flaps from the viewpoints of surgical correction, including reanastomosis and catheter thrombectomy, and nonsurgical procedures, such as a medicinal leech, hyperbaric oxygen, and thrombolytic therapy.

The function of the p75(NTR) neurotrophin receptor (p75(NTR)) in nervous system regeneration is still controversial. Part of that controversy may be due to the fact that p75(NTR) is expressed by both neuronal and glial cell types and may have very distinct and even contradictory roles in each population. In this study, to elucidate the in vivo function of p75(NTR) in Schwann cells during remyelination after peripheral nerve injury, we established a new animal model for p75(NTR)-deficient Schwann cell transplantation in nude mice. We performed quantitative assessments of the functional, histological, and electrophysiological recovery after sciatic nerve injury, and compared them with those of the p75(NTR)(+/+) Schwann cell transplanted animals. At 7-10 weeks after injury, the motor recovery in the p75(NTR)(-/-) Schwann cell transplanted animals was significantly impaired compared with that in the p75(NTR)(+/+) Schwann cell transplanted animals. The lower number of the retrogradely labeled motoneurons and the hypomyelination in the p75(NTR)(-/-) Schwann cell transplanted animals were evident at 6 and 10 weeks after injury. At 10 weeks after injury, the radial growth in the axon caliber was also impaired in the p75(NTR)(-/-) Schwann cell transplanted animals. Measurement of the amount of myelin proteins and the nerve conduction velocity at 10 weeks after injury reflected these results. In summary, the p75(NTR) expression in Schwann cells is important for remyelination process, and the motor recovery after injury is impaired due to impaired axonal growth, remyelination, and radial growth in the axon calibers.

We performed immediate breast reconstruction in 22 patients using rectus abdominis myocutaneous flap accompanied by neurorrhaphy in the past 2 years. In the neurorrhaphy, the 11th intercostal nerve, which controls the sensation of the myocutaneous flap, was anastomosed to the lateral cutaneous branch of the 4th intercostal nerve, which controls the sensation of the breast. Our study included 15 patients, and the postoperative follow-up period was 4 to 24 months, with an average of 14.0 months. For control subjects, there were 16 cases of rectus abdominis myocutaneous flap, whose sensory nerve had not been reconstructed (postoperative follow-up period 11 to 41 months, average 24.1 months). The sensory examination included tests of touch, pain, and temperature. The innervated myocutaneous flap sensation showed gradual recovery at about 6 months after surgery and reached the value of the normal side after about 1 year. In the control subjects, recovery of sensation was not observed at all in the first 10 postoperative months. Then, after more than 1 year, the recovery was gradual and reached the value of the normal side in only some control subjects. Therefore, we consider the present technique useful for recovery of sensation in immediate breast reconstruction.