Molecular and genealogical analysis of grain dormancy in Japanese wheat varieties, with specific focus on MOTHER OF FT AND TFL1 on chromosome 3A.

In the wheat (Triticum aestivum L.) cultivar 'Zenkoujikomugi', a single nucleotide polymorphism (SNP) in the promoter of MOTHER OF FT AND TFL1 on chromosome 3A (MFT-3A) causes an increase in the level of gene expression, resulting in strong grain dormancy. We used a DNA marker to detect the 'Zenkoujikomugi'-type (Zen-type) SNP and examined the genotype of MFT-3A in Japanese wheat varieties, and we found that 169 of 324 varieties carry the Zen-type SNP. In Japanese commercial varieties, the frequency of the Zen-type SNP was remarkably high in the southern part of Japan, but low in the northern part. To examine the relationship between MFT-3A genotype and grain dormancy, we performed a germination assay in three wheat-growing seasons. On average, the varieties carrying the Zen-type SNP showed stronger grain dormancy than the varieties carrying the non-Zen-type SNP. Among commercial cultivars, 'Iwainodaichi' (Kyushu), 'Junreikomugi' (Kinki-Chugoku-Shikoku), 'Kinuhime' (Kanto-Tokai), 'Nebarigoshi' (Tohoku-Hokuriku), and 'Kitamoe' (Hokkaido) showed the strongest grain dormancy in each geographical group, and all these varieties, except for 'Kitamoe', were found to carry the Zen-type SNP. In recent years, the number of varieties carrying the Zen-type SNP has increased in the Tohoku-Hokuriku region, but not in the Hokkaido region.

Distribution of photoperiod-insensitive allele Ppd-A1a and its effect on heading time in Japanese wheat cultivars.

The Ppd-A1 genotype of 240 Japanese wheat cultivars and 40 foreign cultivars was determined using a PCR-based method. Among Japanese cultivars, only 12 cultivars, all of which were Hokkaido winter wheat, carried the Ppd-A1a allele, while this allele was not found in Hokkaido spring wheat cultivars or Tohoku-Kyushu cultivars. Cultivars with a photoperiod-insensitive allele headed 6.9-9.8 days earlier in Kanto and 2.5 days earlier in Hokkaido than photoperiod-sensitive cultivars. The lower effect of photoperiod-insensitive alleles observed in Hokkaido could be due to the longer day-length at the spike formation stage compared with that in Kanto. Pedigree analysis showed that 'Purple Straw' and 'Tohoku 118' were donors of Ppd-A1a and Ppd-D1a in Hokkaido wheat cultivars, respectively. Wheat cultivars recently developed in Hokkaido carry photoperiod-insensitive alleles at a high frequency. For efficient utilization of Ppd-1 alleles in the Hokkaido wheat-breeding program, the effect of Ppd-1 on growth pattern and grain yield should be investigated. Ppd-A1a may be useful as a unique gene source for fine tuning the heading time in the Tohoku-Kyushu region since the effect of Ppd-A1a on photoperiod insensitivity appears to differ from the effect of Ppd-B1a and Ppd-D1a.

Isolation of a wheat (Triticum aestivum L.) mutant in ABA 8'-hydroxylase gene: effect of reduced ABA catabolism on germination inhibition under field condition.

Pre-harvest sprouting, the germination of mature seeds on the mother plant under moist condition, is a serious problem in cereals. To investigate the effect of reduced abscisic acid (ABA) catabolism on germination in hexaploid wheat (Triticum aestivum L.), we cloned the wheat ABA 8'-hydroxyase gene which was highly expressed during seed development (TaABA8'OH1) and screened for mutations that lead to reduced ABA catabolism. In a screen for natural variation, one insertion mutation in exon 5 of TaABA8'OH1 on the D genome (TaABA8'OH1-D) was identified in Japanese cultivars including 'Tamaizumi'. However, a single mutation in TaABA8'OH1-D had no clear effect on germination inhibition in double haploid lines. In a screen for a mutation, one deletion mutant lacking the entire TaABA8'OH1 on the A genome (TaABA8'OH1-A), TM1833, was identified from gamma-ray irradiation lines of 'Tamaizumi'. TM1833 (a double mutant in TaABA8'OH1-A and TaABA8'OH1-D) showed lower TaABA8'OH1 expression, higher ABA content in embryos during seed development under field condition and lower germination than those in 'Tamaizumi' (a single mutant in TaABA8'OH1-D). These results indicate that reduced ABA catabolism through mutations in TaABA8'OH1 may be effective in germination inhibition in field-grown wheat.

Crohn's disease and stroke in a young adult.

A 36-year-old man with a 21-year history of Crohn's disease suddenly developed left hemiparesis. He did not have atherosclerotic risk factors on admission, but he had marked dehydration which was likely due to prolonged home intravenous hyper-alimentation. Brain MRI revealed lacunar infarction in the right anterior corona radiata. An anticoagulation drug and a free-oxide scavenger successfully reversed his neurological deficits almost completely. Stroke in young adults less than 40 years old is extremely rare; therefore, we conclude that Crohn's disease can be a risk factor for acute ischemic stroke in our case, due most probably to dehydration and other complex mechanisms.

Distribution of photoperiod-insensitive alleles Ppd-B1a and Ppd-D1a and their effect on heading time in Japanese wheat cultivars.

The genotypes of photoperiod response genes Ppd-B1 and Ppd-D1 in Japanese wheat cultivars were determined by a PCR-based method, and heading times were compared among genotypes. Most of the Japanese wheat cultivars, except those from the Hokkaido region, carried the photoperiod-insensitive allele Ppd-D1a, and heading was accelerated 10.3 days compared with the Ppd-D1b genotype. Early cultivars with Ppd-D1a may have been selected to avoid damage from preharvest rain. In the Hokkaido region, Ppd-D1a frequency was lower and heading date was late regardless of Ppd-D1 genotype, suggesting another genetic mechanism for late heading in Hokkaido cultivars. In this study, only 11 cultivars proved to carry Ppd-B1a, and all of them carried another photoperiod-insensitive allele, Ppd-D1a. The Ppd-B1a/Ppd-D1a genotype headed 6.7 days earlier than the Ppd-B1b/Ppd-D1a genotype, indicating a significant effect of Ppd-B1a in the genetic background with Ppd-D1a. Early-maturity breeding in Japan is believed to be accelerated by the introduction of the Ppd-B1a allele into medium-heading cultivars carrying Ppd-D1a. Pedigree analysis showed that Ppd-B1a in three extra-early commercial cultivars was inherited from 'Shiroboro 21' by early-heading Chugoku lines bred at the Chugoku Agriculture Experimental Station.

Measurement of whole blood factor Xa-activated clotting time during hemodialysis with low-molecular-weight heparin.

PURPOSE: To determine whole blood factor Xa-activated clotting time (XaACT), a test for monitoring low-molecular-weight heparins (LMWHs). METHODS: Blood was obtained from six healthy volunteers. Dalteparin, a LMWH, was mixed with the blood to concentrations of 0,05 and 1.0IU·ml-1. XaACT, activated clotting time (ACT), and activated partial thromboplastin time (APTT) were measured at each dalteparin concentration. XaACT of blood from the outflow and inflow sides of the blood circuit in seven hemodialysis patients was measured before and after bolus administration of 1000 IU of dalteparin, followed by continuous infusion at a rate of 500IU·h-1. RESULTS: XaACT, ACT, and APTT in dalteparin-containing blood from volunteers were correlated with dalteparin concentration (y=312.8x+86.4;r 2=0.88;P<0.001,y=41.8x +113.5;r 2=0.83;P<0.001, andy=59.5x+38.8;r 2=0.80;P<0.001, respectively). The regression slope of XaACT was steeper than those of ACT and APTT (P<0.001). In hemodialysis patients, dalteparin increased XaACT on the outflow and inflow sides of the circuit (P<0.001,P<0.05, respectively). CONCLUSION: The measurement of XaACT can be employed to monitor LMWHs in clinical settings.