Designing rice panicle architecture via developmental regulatory genes.

Rice panicle architecture displays remarkable diversity in branch number, branch length, and grain arrangement; however, much remains unknown about how such diversity in patterns is generated. Although several genes related to panicle branch number and panicle length have been identified, how panicle branch number and panicle length are coordinately regulated is unclear. Here, we show that panicle length and panicle branch number are independently regulated by the genes Prl5/OsGA20ox4, Pbl6/APO1, and Gn1a/OsCKX2. We produced near-isogenic lines (NILs) in the Koshihikari genetic background harboring the elite alleles for Prl5, regulating panicle rachis length; Pbl6, regulating primary branch length; and Gn1a, regulating panicle branching in various combinations. A pyramiding line carrying Prl5, Pbl6, and Gn1a showed increased panicle length and branching without any trade-off relationship between branch length or number. We successfully produced various arrangement patterns of grains by changing the combination of alleles at these three loci. Improvement of panicle architecture raised yield without associated negative effects on yield-related traits except for panicle number. Three-dimensional (3D) analyses by X-ray computed tomography (CT) of panicles revealed that differences in panicle architecture affect grain filling. Importantly, we determined that Prl5 improves grain filling without affecting grain number.

A leaf-emanated signal orchestrates grain size and number in response to maternal resources.

In plants, variations in seed size and number are outcomes of different reproductive strategies. Both traits are often environmentally influenced, suggesting that a mechanism exists to coordinate these phenotypes in response to available maternal resources. Yet, how maternal resources are sensed and influence seed size and number is largely unknown. Here, we report a mechanism that senses maternal resources and coordinates grain size and number in the wild rice Oryza rufipogon, a wild progenitor of Asian cultivated rice. We showed that FT-like 9 (FTL9) regulates both grain size and number and that maternal photosynthetic assimilates induce FTL9 expression in leaves to act as a long-range signal that increases grain number and reduces size. Our findings highlight a strategy that benefits wild plants to survive in a fluctuating environment. In this strategy, when maternal resources are sufficient, wild plants increase their offspring number while preventing an increase in offspring size by the action of FTL9, which helps expand their habitats. In addition, we found that a loss-of-function allele (ftl9) is prevalent among wild and cultivated populations, offering a new scenario in the history of rice domestication.

Collection, preservation and distribution of Oryza genetic resources by the National Bioresource Project RICE (NBRP-RICE).

Biological resources are the basic infrastructure of bioscience research. Rice (Oryza sativa L.) is a good experimental model for research in cereal crops and monocots and includes important genetic materials used in breeding. The availability of genetic materials, including mutants, is important for rice research. In addition, Oryza species are attractive to researchers for both finding useful genes for breeding and for understanding the mechanism of genome evolution that enables wild plants to adapt to their own habitats. NBRP-RICE contributes to rice research by promoting the usage of genetic materials, especially wild Oryza accessions and mutant lines. Our activity includes collection, preservation and distribution of those materials and the provision of basic information on them, such as morphological and physiological traits and genomic information. In this review paper, we introduce the activities of NBRP-RICE and our database, Oryzabase, which facilitates the access to NBRP-RICE resources and their genomic sequences as well as the current situation of wild Oryza genome sequencing efforts by NBRP-RICE and other institutes.

Diverse panicle architecture results from various combinations of Prl5/GA20ox4 and Pbl6/APO1 alleles.

Panicle architecture directly affects crop productivity and is a key target of high-yield rice breeding. Panicle length strongly affects panicle architecture, but the underlying regulatory mechanisms are largely unknown. Here, we show that two quantitative trait loci (QTLs), PANICLE RACHIS LENGTH5 (Prl5) and PRIMARY BRANCH LENGTH6 (Pbl6), independently regulate panicle length in rice. Prl5 encodes a gibberellin biosynthesis enzyme, OsGA20ox4. The expression of Prl5 was higher in young panicles resulting in panicle rachis elongation. Pbl6 is identical to ABERRANT PANICLE ORGANIZATION 1 (APO1), encoding an F-box-containing protein. We found a novel function that higher expression of Pbl6 is responsible for primary branch elongation. RNA-seq analysis revealed that these two genes independently regulate panicle length at the level of gene expression. QTL pyramiding of both genes increased panicle length and productivity. By combining these two genes in various combinations, we designed numerous panicle architecture without trade-off relationship.

Comprehensive panicle phenotyping reveals that qSrn7/FZP influences higher-order branching.

Rice grain number directly affects crop yield. Identifying alleles that improve panicle architecture would greatly aid the development of high-yield varieties. Here, we show that the quantitative trait locus qSrn7 contains rice FRIZZY PANICLE (FZP), a previously reported gene encoding an ERF transcription factor that promotes floral transition. Reduced expression of FZP in the reproductive stage increases the extent of higher order branching of the panicle, resulting in increased grain number. Genotype analysis of this gene in cultivars from the publicly available National Institute of Agrobiological Sciences (NIAS) Core Collection demonstrated that the extent of higher order branching, especially in the upper panicle, was increased in those cultivars carrying the FZP allele associated with qSrn7. Furthermore, chromosome segment substitution lines resulting from a cross between Koshihikari and Kasalath, the latter of which carries qSrn7/FZP, also showed that upper panicle higher order branching and grain yield were increased by qSrn7/FZP. Our findings indicate that qSrn7/FZP influences panicle branching pattern and is thus useful in the breeding of high-yield rice varieties.

The efficiency and adverse events of radiotherapy with cetuximab for Japanese head and neck cancer patients.

OBJECTIVES: Radiotherapy with cisplatin (Chemoradiotherapy, CRT) has long been one of the standard treatments for head and neck squamous cell cancer (HNSCC). Approval of cetuximab for the treatment of HNSCC has made radiotherapy with cetuximab (Bioradiotherapy, BRT) a new treatment option for HNSCC. Reports of BRT in the Japanese written in English up to now is only the phase II study, though it includes only 22 patients. Also on the nature of the clinical Phase II trial, sampling bias of cases may exist. Here we report the treatment completion rate, response rate and frequency of adverse events of BRT in Japanese patients with HNSCC in English for the first time. In association with this, we examine the issues related to BRT in Japanese patients. PATIENTS AND METHODS: The subjects consisted of patients with HNSCC who underwent BRT as the first curative treatment (45 cases). Their treatment completion rate, response rate and frequency of adverse events were examined. RESULTS: Of the 45patients, 42 were male and 3 were female. The mean age of the patients was 64 (range from 40 to 86). Adverse events of Grade3 or more were 12 cases (27%) of dermatitis, 31 cases (69%) of mucositis/stomatitis, 6 cases (13%) of interstitial pneumonia. The complication rate of pulmonary emphysema in those who developed interstitial pneumonia and those who did not were 83% and 21%, respectively. The BRT completion rate was 78%, and the response rate was 84%. CONCLUSION: BRT is sufficiently tolerable and have high response rate even for the Japanese, but we should recognize that BRT is not a minimally invasive and easily manageable treatment.

Extent of thyroid resection and thyroid function after postoperative radiotherapy following total laryngectomy or total pharyngo-laryngo-esophagectomy.

OBJECTIVE: Concurrent chemoradiotherapy (CCRT) is often performed after total pharyngo-laryngo-esophagectomy (TPLE) or total laryngectomy (TL). Hypothyroidism is one of the side-effects of CCRT. The objective of this study was to ascertain the timing of onset and severity of latent hypothyroidism among patients who underwent radiotherapy (RT) or CCRT after TPLE or TL, using thyroid-stimulating hormone (TSH) as a biomarker, and to explore methods of preventing its development. METHODS: Participants comprised 21 patients who underwent these treatments at Tokyo Medical University Hachioji Medical Center between May 2009 and December 2013. TSH, free thyroxine 3, and free thyroxine 4 levels were used as indicators of thyroid function, and thyroid hormone was administered for TSH levels ≥15 µU/mL. RESULTS: Post-radiotherapeutic TSH levels in 17 of the 21 patients (81%) were not within the reference value, and 10 (48%) required thyroid hormone therapy. Pharmacotherapy was initiated within 1 year in 5 of these 10 patients (50%), and between 1 and 3 years in the remaining 5 patients. No patient who did not undergo thyroidectomy required hormone therapy. Early evaluation of thyroid function appears important when postoperative RT, including CCRT, is performed in combination with TPLE or TL. CONCLUSION: Our study suggested that postoperative CCRT or RT after TPLE or TL, especially hemithyroidectomy, carries a high risk for hypothyroidism.