A novel role of BELL1-like homeobox genes, PENNYWISE and POUND-FOOLISH, in floral patterning

Flowers are determinate shoots comprised of perianth and reproductive organs displayed in a whorled phyllotactic pattern. Floral organ identity genes display region-specific expression patterns in the developing flower. In Arabidopsis, floral organ identity genes are activated by LEAFY (LFY), which functions with region-specific co-regulators, UNUSUAL FLORAL ORGANS (UFO) and WUSCHEL (WUS), to up-regulate homeotic genes in specific whorls of the flower. PENNYWISE (PNY) and POUND-FOOLISH (PNF) are redundant functioning BELL1-like homeodomain proteins that are expressed in shoot and floral meristems. During flower development, PNY functions with a co-repressor complex to down-regulate the homeotic gene, AGAMOUS (AG), in the outer whorls of the flower. However, the function of PNY as well as PNF in regulating floral organ identity in the central whorls of the flower is not known. In this report, we show that combining mutations in PNY and PNF enhance the floral patterning phenotypes of weak and strong alleles of lfy, indicating that these BELL1-like homeodomain proteins play a role in the specification of petals, stamens and carpels during flower development. Expression studies show that PNY and PNF positively regulate the homeotic genes, APETALA3 and AG, in the inner whorls of the flower. Moreover, PNY and PNF function in parallel with LFY, UFO and WUS to regulate homeotic gene expression. Since PNY and PNF interact with the KNOTTED1-like homeodomain proteins, SHOOTMERISTEMLESS (STM) and KNOTTED-LIKE from ARABIDOPSIS THALIANA2 (KNAT2) that regulate floral development, we propose that PNY/PNF-STM and PNY/PNF-KNAT2 complexes function in the inner whorls to regulate flower patterning events.     

海南坡鹿的起源、进化及保护

坡鹿是世界濒危物种,三个亚种分布在东南亚大陆,仅海南坡鹿种群分布在中国海南岛.2003年,国际社会的专家和学者提出了将海南坡鹿引入泰国亚种原分布区,重建已经绝灭野生种群的建议.在此种情况下,明确海南坡鹿的起源、与其它亚种间的系统发生关系、以及遗传多样性水平对有效保护坡鹿具有重要意义.本研究以线粒体DNA D-loop区490 bp基因片段为分子标记,比较分析了海南坡鹿、泰国亚种和缅甸亚种共35个样本的序列差异.我们所测的样本中,总共发现4种单倍型.所有21个海南坡鹿样品共享1种单倍型.利用最大似然法(ML)、最大简约法(MP)、邻接法(NJ)和贝叶斯法(Bayesian)构建的系统进化树表明海南坡鹿种群与泰国亚种的关系较近.但是,二者也发生一定程度的遗传分化.海南坡鹿与泰国亚种的遗传距离均值为0.026.我们推测海南坡鹿可能是在更新世冰期(69万年前)通过陆桥由东南亚大陆迁入中国海南岛.我们的结论说明海南坡鹿的遗传多样性很低,并且已独立进化很长时间.因此,我们不支持将海南坡鹿引入泰国亚种的原分布区,重建已经绝灭的野生种群的设想和建议.我们建议将海南坡鹿与泰国亚种分别作为两个独立的进化显著单元(ESUs)进行管理.     

Root and shoot traits responses to phosphorus deficiency and QTL analysis at seedling stage using introgression lines of rice

Phosphorous （P） deficiency is a major restraint factor for crop production and plants have developed several mechanisms to adapt to low P stress. In this study, a set of 271 introgression lines （ILs） were used to characterize the responses of seedlings to low P availability and to identify QTLs for root traits, biomass, and plant height under P-deficiency and P-sufficiency conditions. Plant height, total dry weight, shoot dry weight, and root number were inhibited under P-deficiency, whereas maximum root length （MRL） and root-shoot ratio （RS） were induced by P-deficiency stress. Relative MRL （RMRL, the ratio of MRL under P-deficiency to MRL under P-sufficiency con- dition） and relative RS （RRS） were used to evaluate P-deficiency tolerance at the seedling stage. A total of 24 additive QTLs and 29 pairs of epistatic QTLs were detected, but only qRN4 was detected in both conditions. This suggested that different mechanisms may exist in both P supply levels. QTLs for adaptive traits （RMRL, RRS, RRV, and RRDW） and qRN4 consistently expressed to increase trait stability may contribute to P-deficiency tolerance. Twelve intervals were cluster regions of QTLs for P-deficiency tolerance, and one QTL （qRRSS） showed pleiotropic effects on P-deficiency tolerance and drought tolerance. These interesting QTLs can be used in marker-assisted breeding through the target ILs.     

经寰枕间隙侧方穿刺移植人脐血单个核细胞对难治性神经系统疾病的疗效分析

目的探讨寰枕间隙侧方穿刺术移植人脐血单个核细胞治疗难治性神经系统疾病的可行性和安全性。 方法应用寰枕间隙侧方穿刺术对230例患者进行450次人脐血单个核细胞治疗,观察治疗中及治疗后有无不良反应和并发症,对比治疗前后血液分析、血沉、生化全项、出凝血机制和肿瘤标记物数值,同时观察患者治疗前后病情转归,采用配对比较t检验进行统计学分析。 结果所有患者治疗后均无头痛、感染、皮疹、血肿形成等不良反应和其它移植并发症出现。32例（7.1%）治疗后出现一过性血压升高,8例（1.8%）出现一过性发热,10例（2.2%）穿刺时诉穿刺处深部软组织胀痛,拔针后疼痛消失。患者白细胞计数治疗前（7.9±1.1）×10⁹个/?L和治疗后3个月（8.0±1.3）×10⁹个/L相比差异无统计学意义（t =?0.891,P?=?0.374）,谷丙转氨酶治疗前（31.9±5.8）U/L和治疗后3个月（32.4±6.2）U/L相比差异无统计学意义（t?=?0.893,P?=?0.372）,球蛋白治疗前（22.1±1.7）g/L和治疗后3个月（21.8±1.8）g/L相比差异无统计学意义（t?=?0.838,P?=?0.066）,AFP治疗前（9.9±1.6）μg/L和治疗后3个月（10.1±1.7）μg/L相比差异无统计学意义（t?=?1.299,P?=?0.195）,患者血液学指标（血常规+血沉、生化全项、全身肿瘤标记物、病毒筛查、出凝血机制）在治疗前后无统计学差异。183例患者治疗有效,有效率79.6%。 结论寰枕间隙侧方穿刺术移植人脐血单个核细胞治疗难治性神经系统疾病是安全可行并可能有效的。     

A functional-structural model of rice linking quantitative genetic information with morphological development and physiological processes

Background and Aims

Although quantitative trait loci (QTL) analysis of yield-related traits for rice has developed rapidly, crop models using genotype information have been proposed only relatively recently. As a first step towards a generic genotype–phenotype model, we present here a three-dimensional functional–structural plant model (FSPM) of rice, in which some model parameters are controlled by functions describing the effect of main-effect and epistatic QTLs.

Methods

The model simulates the growth and development of rice based on selected ecophysiological processes, such as photosynthesis (source process) and organ formation, growth and extension (sink processes). It was devised using GroIMP, an interactive modelling platform based on the Relational Growth Grammar formalism (RGG). RGG rules describe the course of organ initiation and extension resulting in final morphology. The link between the phenotype (as represented by the simulated rice plant) and the QTL genotype was implemented via a data interface between the rice FSPM and the QTLNetwork software, which computes predictions of QTLs from map data and measured trait data.

Key Results

Using plant height and grain yield, it is shown how QTL information for a given trait can be used in an FSPM, computing and visualizing the phenotypes of different lines of a mapping population. Furthermore, we demonstrate how modification of a particular trait feeds back on the entire plant phenotype via the physiological processes considered.

Conclusions

We linked a rice FSPM to a quantitative genetic model, thereby employing QTL information to refine model parameters and visualizing the dynamics of development of the entire phenotype as a result of ecophysiological processes, including the trait(s) for which genetic information is available. Possibilities for further extension of the model, for example for the purposes of ideotype breeding, are discussed.Key words: Functional–structural plant model, ecophysiology, QTL analysis, plant modelling, quantitative genetics