Association mapping of stigma and spikelet characteristics in rice (Oryza sativa L.)

Stigma and spikelet characteristics play an essential role in hybrid seed production. A mini-core of 90 accessions developed from USDA rice core collection was phenotyped in field grown for nine traits of stigma and spikelet and genotyped with 109 DNA markers, 108 SSRs plus an indel. Three major clusters were built upon Rogers’ genetic distance, indicative of indicas, and temperate and tropical japonicas. A mixed linear model combining PC-matrix and K-matrix was adapted for mapping marker-trait associations. Resulting associations were adjusted using false discovery rate technique. We identified 34 marker-trait associations involving 22 SSR markers for eight traits. Four markers were associated with single stigma exsertion (SStgE), six with dual exsertion (DStgE) and five with total exsertion. RM5_Chr1 played major role indicative of high regression with not only DStgE but also SStgE. Four markers were associated with spikelet length, three with width and seven with L/W ratio. Numerous markers were co-associated with multiple traits that were phenotypically correlated, i.e. RM12521_Chr2 associated with all three correlated spikelet traits. The co-association should improve breeding efficiency because single marker could be used to assist breeding for multiple traits. Indica entry 1032 (cultivar 50638) and japonica entry 671 (cultivar Linia 84 Icar) with 80.65 and 75.17% of TStgE, respectively are recommended to breeder for improving stigma exsertion

Experimental-numerical analysis of added resistance to container ships under presence of wind-wave loads.

Experimental and numerical analyses performed on a scaled-down model of a 1900TEU container-ship are reported herein. Wind-tunnel and towing-tank experiments along with computational-fluid-dynamic simulations were performed to obtain (1) wind-load coefficients for superstructure of container ship at different wind angles under full-load operating conditions; (2) wave resistance of the model sans the superstructure under different wave conditions; and (3) combined wind-wave resistance of the model in the head waves coupled with a fluctuating wind. Wind-tunnel experiments were first performed to determine wind-load coefficients concerning of the superstructure at different wind angles. Subsequently, the obtained wind-load coefficients from the wind tunnel test were compared against numerical and empirically obtained results to validate the applicability of the applied numerical methods. Next, the wave-induced resistance to ship motion was investigated via a series of towing-tank experiments and numerical simulations to analyze the resistance and motion of ship under wavy conditions. Finally, characteristics of the added resistance to ship motion under conditions of combined wind-wave load were analyzed, and the coupling between ship motion and combined wind-wave load was used to investigate the changes in added resistance under different load scenarios. The results reveal that combined wind-wave load causes the resistance to ship motion to exceed the algebraic sum of the corresponding resistances under standalone wind- and wave-load conditions. The additional resistance was observed to be a combined manifestation of resistances induced by ship motion and wave-parameter alterations

Assessing rainfall erosivity changes over China through a Bayesian averaged ensemble of high-resolution climate models

Spatiotemporal variation in rainfall erosivity resulting from changes in rainfall characteristics due to climate change has implications for soil erosion in developing countries. To promote soil and water conservation planning, it is essential to understand past and future changes in rainfall erosivity and their implications on a national scale. In this study, we present an approach that uses a Bayesian model averaging (BMA) method to merge multiple regional climate models (RCMs), thereby improving the reliability of climate-induced rainfall erosivity projections. Our multi-climate model and multi-emission scenario approach utilize five RCMs and two Representative Concentration Pathways (RCP4.5 and RCP8.5) scenarios for the baseline period (1986–2005) and future periods (2071–2090) to characterize the spatiotemporal projection of rainfall erosivity and assess variations in China. Our results indicate that the two models outperform other models in reproducing the spatial distribution and annual cycle of rainfall erosivity in China. Moreover, we found an increasing trend in the annual rainfall erosivity from the baseline climate up to the RCMs for all models, with an average change in erosivity of approximately 10.9% and 14.6% under RCP4.5 and RCP8.5, respectively. Our BMA results showed an increase in the absolute value of rainfall erosivity by 463.3 and 677.0 MJ·mm·hm ^−2 ·h ^−1 , respectively, in the South China red soil region and the Southwest China karst region under the RCP8.5 scenario. This increase indicates that climate warming will significantly enhance the potential erosion capacity of rainfall in these regions. Additionally, our study revealed that the Southwest China karst region and the Northwest China Loess Plateau region are more sensitive to radiation forcing. To mitigate the risk of soil erosion caused by climate change, it is necessary to consider changes in rainfall erosivity, local soil conditions, vegetation coverage, and other factors in different regions and take appropriate soil and water conservation measures

Progress in Collaborative Improvement of High Quality, Yield, and Disease Resistance Breeding of Approved Rice Varieties in Guangdong from 2004 to 2022

This article succinctly outlines the requirements for rice quality in Guangdong Province and the role of government regulatory policies in advancing high-quality rice breeding. By collecting the regional trial data of 1 101 rice varieties approved by Guangdong Province from 2004 to 2022, the number of varieties meeting the national or ministerial standards approved in each year were counted, and the progress of high-quality rice breeding in Guangdong was evaluated from the perspectives of quality index, resistance and yield. From 2004 to 2022, 106 varieties (combinations) meeting the quality of national standard (ministerial standard) (9.63% of all approved varieties) level Ⅰ and 320 varieties (combinations) reaching the quality of national standard (ministerial standard) (29.06%) level Ⅱ were approved by Guangdong. Notably, early season varieties exhibited lower quality rates compared with late season varieties. For rice quality traits, early-season trial varieties displayed lower compliance rates in the quality of national standard (ministerial standard) level Ⅱ, with chalkiness and chalky grain rate of 41.8% and 43.5%, respectively; the amylose content compliance rate in early-season trial varieties was only 37.32%, indicating that key improvements should be conducted in these three areas for new variety breeding. The average yield of rice varieties with quality meeting national standard level Ⅱ or above has consistently risen, indicating synergistic improvements in yield and rice quality during the high-quality rice breeding in Guangdong. Varieties meeting the national standard (ministerial standard) level Ⅱ or above also showed promising resistance rates against rice blast disease (85% at medium resistance or above) and bacterial blight disease (22.2% at medium resistance or above). Generally, while the percentage of hybrid rice varieties meeting high-quality standards is increasing, there is still a notable gap compared to conventional rice breeding. The proportion of high-quality rice varieties in Guangdong has been steadily growing, with a positive trend in "excellent, abundant and resistant" varieties. However, further optimization is possible. To cultivate high-quality rice varieties with double resistances, efforts should be put to enhance resistance to bacterial wilt disease. The evaluation and utilization of specific germplasm resources like local varieties should be increased to diversify the genetic background. This approach helps avoid variety homogenization, improves disease and stress resistance and strengthens the synergy between traditional and molecular breeding, enhancing overall breeding efficiency

Comparative Proteome Analyses Reveal that Nitric Oxide Is an Important Signal Molecule in the Response of Rice to Aluminum Toxicity

Acidic soils inhibit crop yield and reduce grain quality. One of the major contributing factors to acidic soil is the presence of soluble aluminum (Al³⁺) ions, but the mechanisms underlying plant responses to Al³⁺ toxicity remain elusive. Nitric oxide (NO) is an important messenger and participates in various plant physiological responses. Here, we demonstrate that Al³⁺ induced an increase of NO in rice seedlings; adding exogenous NO alleviated the Al³⁺ toxicity related to rice growth and photosynthetic capacity, effects that could be reversed by suppressing NO metabolism. Comparative proteomic analyses successfully identified 92 proteins that showed differential expression after Al³⁺ or NO treatment. In particular, some of the proteins are involved in reactive oxygen species (ROS) and reactive nitrogen species (RNS) metabolism. Further analyses confirmed that NO treatment reduced Al³⁺-induced ROS and RNS toxicities by increasing the activities and protein expression of antioxidant enzymes, as well as <i>S</i>-nitrosoglutathione reductase (GSNOR). Suppressing GSNOR enzymatic activity aggravated Al³⁺ damage to rice and increased the accumulation of RNS. NO treatment altered the expression of proteins associated with cell wall synthesis, cell division and cell structure, calcium signaling and defense responses. On the basis of these results, we propose that NO activates multiple pathways that enhance rice adaptation to Al³⁺ toxicity. Such findings may be applicable to crop engineering to enhance yield and improve stress tolerance

Proteomic analysis of the defense response to Magnaporthe oryzae in rice harboring the blast resistance gene Piz-t

Abstract Background Rice blast (caused by Magnaporthe oryzae) is one of the most destructive diseases of rice. While many blast resistance (R) genes have been identified and deployed in rice cultivars, little is known about the R gene-mediated defense mechanism. We used a rice transgenic line harboring the resistance gene Piz-t to investigate the R gene-mediated resistance response to infection. Results We conducted comparative proteome profiling of the Piz-t transgenic Nipponbare line (NPB-Piz-t) and wild-type Nipponbare (NPB) inoculated with M. oryzae at 24, 48, 72 h post-inoculation (hpi) using isobaric tags for relative and absolute quantification (iTRAQ) analysis. Comparative analysis of the response of NPB-Piz-t to the avirulent isolate KJ201 and the virulent isolate RB22 identified 114 differentially expressed proteins (DEPs) between KJ201-inoculated NPB-Piz-t (KJ201-Piz-t) and mock-treated NPB-Piz-t (Mock-Piz-t), and 118 DEPs between RB22-inoculated NPB-Piz-t (RB22-Piz-t) and Mock-Piz-t. Among the DEPs, 56 occurred commonly in comparisons KJ201-Piz-t/Mock-Piz-t and RB22-Piz-t/Mock-Piz-t. In a comparison of the responses of NPB and NPB-Piz-t to isolate KJ201, 93 DEPs between KJ201-Piz-t and KJ201-NPB were identified. DEPs in comparisons KJ201-Piz-t/Mock-Piz-t, RB22-Piz-t/Mock-Piz-t and KJ201-Piz-t/KJ201-NPB contained a number of proteins that may be involved in rice response to pathogens, including pathogenesis-related (PR) proteins, hormonal regulation-related proteins, defense and stress response-related proteins, receptor-like kinase, and cytochrome P450. Comparative analysis further identified 7 common DEPs between the comparisons KJ201-Piz-t/KJ201-NPB and KJ201-Piz-t/RB22-Piz-t, including alcohol dehydrogenase I, receptor-like protein kinase, endochitinase, similar to rubisco large subunit, NADP-dependent malic enzyme, and two hypothetical proteins. Conclusions Our results provide a valuable resource for discovery of complex protein networks involved in the resistance response of rice to blast fungus

Comparative Proteome Analyses Reveal that Nitric Oxide Is an Important Signal Molecule in the Response of Rice to Aluminum Toxicity

Acidic soils inhibit crop yield and reduce grain quality. One of the major contributing factors to acidic soil is the presence of soluble aluminum (Al³⁺) ions, but the mechanisms underlying plant responses to Al³⁺ toxicity remain elusive. Nitric oxide (NO) is an important messenger and participates in various plant physiological responses. Here, we demonstrate that Al³⁺ induced an increase of NO in rice seedlings; adding exogenous NO alleviated the Al³⁺ toxicity related to rice growth and photosynthetic capacity, effects that could be reversed by suppressing NO metabolism. Comparative proteomic analyses successfully identified 92 proteins that showed differential expression after Al³⁺ or NO treatment. In particular, some of the proteins are involved in reactive oxygen species (ROS) and reactive nitrogen species (RNS) metabolism. Further analyses confirmed that NO treatment reduced Al³⁺-induced ROS and RNS toxicities by increasing the activities and protein expression of antioxidant enzymes, as well as <i>S</i>-nitrosoglutathione reductase (GSNOR). Suppressing GSNOR enzymatic activity aggravated Al³⁺ damage to rice and increased the accumulation of RNS. NO treatment altered the expression of proteins associated with cell wall synthesis, cell division and cell structure, calcium signaling and defense responses. On the basis of these results, we propose that NO activates multiple pathways that enhance rice adaptation to Al³⁺ toxicity. Such findings may be applicable to crop engineering to enhance yield and improve stress tolerance

Anatomical Database and Atlas of Chinese Woods

International audienceChina has the most diverse plant vegetation in the northern hemisphere. This diversity includes more than 30,000 species of higher plants, approximately one third of which are woody. Plant species face many threats to survival, with current extinction rates reported to be higher than in pre-historic times. The higher rates of extinction is not just because of climate change, but also due to exploitation, habitat loss, and environmental pollution all over the world. Drastic changes in the environment and economy have taken place in the last two to three decades in China. For instance, land development has advanced much more rapidly in all provinces in parallel with the economic boom. Consequently, a number of traditional folk-houses have been destroyed or modified for other economic purposes. At the same time, a great number of historic or archaeological sites have been excavated during land development throughout the country. In many cases, archaeological sites are filled with large amounts of timber and logs. This situation has given opportunities for wood scientists and archaeologists to get involved in identification of traditionally used wood species, and helps in the restoration of cultural heritage. The authors have been actively involved in the identification of wood components of cultural treasures such as temples and shrines, and of Buddhist statues, and archaeological wooden remaims in China and Japan, to understand “wood culture” from a scientific aspect. However, references for identifying wood species in China are limited. The most reliable and useful book for this purpose is an out-of-print book “Wood atlas in China” (中国木材�, zhong guo mu cai zhi), which describes anatomical features of wood from 36 softwood species and 315 hardwood species, along with microscopic images from 52 softwood and 240 hardwood species. However, there are about 10,000 or more species of woody plants growing in China, including shrubs and vines. A reference with description of a limited number of woody plant species will not be sufficient for identification of wood species excavated from archaeological sites, or for reconstruction of the forest vegetation from the past. In view of insufficient information of the anatomical features of various wood species in China, we started to build the database as part of a mission to keep a record of the diversity of microscopic features of wood from China. The publication under the title Anatomical Database and Atlas of Chinese Woods will be of some help not only in the scientific understanding of wood culture, but also in the prevention of illegal logging of trees and forest conservation, and the authors have worked together for many years to prepare microscope slides of various Chinese wood specimens, describe microscopic features and take microscope images. In consideration of the biodiversity of Chinese trees, approximately 1,300 woody species including the CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora)-listed, endangered and endemic trees are covered in this database.La Chine possède la végétation végétale la plus diversifiée de l'hémisphère nord. Cette diversité comprend plus de 30 000 espèces de plantes supérieures, dont environ un tiers sont ligneuses. Les espèces végétales sont confrontées à de nombreuses menaces pour leur survie, et les taux d'extinction actuels seraient plus élevés qu'à l'époque préhistorique. L'augmentation des taux d'extinction n'est pas seulement due au changement climatique, mais aussi à l'exploitation, à la perte d'habitat et à la pollution environnementale dans le monde entier. Des changements radicaux dans l'environnement et l'économie ont eu lieu au cours des deux ou trois dernières décennies en Chine. Par exemple, l'aménagement du territoire a progressé beaucoup plus rapidement dans toutes les provinces, parallèlement au boom économique. En conséquence, un certain nombre de maisons folkloriques traditionnelles ont été détruites ou modifiées à d'autres fins économiques. Dans le même temps, un grand nombre de sites historiques ou archéologiques ont été mis à jour lors de l'aménagement du territoire dans tout le pays. Dans de nombreux cas, les sites archéologiques sont remplis de grandes quantités de bois et de grumes. Cette situation a donné l'occasion aux scientifiques du bois et aux archéologues de s'impliquer dans l'identification des espèces de bois traditionnellement utilisées, et de contribuer à la restauration du patrimoine culturel. Les auteurs ont participé activement à l'identification des composants en bois de trésors culturels tels que des temples et des sanctuaires, des statues bouddhistes et des vestiges archéologiques en bois en Chine et au Japon, afin de comprendre la "culture du bois" d'un point de vue scientifique. Cependant, les références pour l'identification des espèces de bois en Chine sont limitées. Le livre le plus fiable et le plus utile à cet effet est un ouvrage épuisé intitulé "Atlas du bois en Chine" (中国木材�, zhong guo mu cai zhi), qui décrit les caractéristiques anatomiques du bois de 36 espèces de résineux et de 315 espèces de feuillus, ainsi que les images microscopiques de 52 espèces de résineux et de 240 espèces de feuillus. Cependant, il existe environ 10 000 espèces ou plus de plantes ligneuses poussant en Chine, y compris des arbustes et des plantes grimpantes. Une référence avec la description d'un nombre limité d'espèces de plantes ligneuses ne sera pas suffisante pour l'identification des espèces de bois excavées des sites archéologiques, ou pour la reconstruction de la végétation forestière du passé. Compte tenu de l'insuffisance des informations sur les caractéristiques anatomiques des différentes espèces de bois en Chine, nous avons commencé à construire la base de données dans le cadre d'une mission visant à conserver un registre de la diversité des caractéristiques microscopiques du bois en Chine. La publication sous le titre Base de données et atlas anatomiques des bois chinois sera d'une certaine utilité non seulement pour la compréhension scientifique de la culture du bois, mais aussi pour la prévention de l'abattage illégal des arbres et la conservation des forêts. Les auteurs ont travaillé ensemble pendant de nombreuses années pour préparer des lames de microscope de divers spécimens de bois chinois, décrire les caractéristiques microscopiques et prendre des images au microscope. Compte tenu de la biodiversité des arbres chinois, cette base de données couvre environ 1 300 espèces ligneuses, y compris les arbres répertoriés par la CITES (Convention sur le commerce international des espèces de faune et de flore sauvages menacées d'extinction), les arbres menacés et les arbres endémiques

Comparative Proteome Analyses Reveal that Nitric Oxide Is an Important Signal Molecule in the Response of Rice to Aluminum Toxicity

Acidic soils inhibit crop yield and reduce grain quality. One of the major contributing factors to acidic soil is the presence of soluble aluminum (Al³⁺) ions, but the mechanisms underlying plant responses to Al³⁺ toxicity remain elusive. Nitric oxide (NO) is an important messenger and participates in various plant physiological responses. Here, we demonstrate that Al³⁺ induced an increase of NO in rice seedlings; adding exogenous NO alleviated the Al³⁺ toxicity related to rice growth and photosynthetic capacity, effects that could be reversed by suppressing NO metabolism. Comparative proteomic analyses successfully identified 92 proteins that showed differential expression after Al³⁺ or NO treatment. In particular, some of the proteins are involved in reactive oxygen species (ROS) and reactive nitrogen species (RNS) metabolism. Further analyses confirmed that NO treatment reduced Al³⁺-induced ROS and RNS toxicities by increasing the activities and protein expression of antioxidant enzymes, as well as <i>S</i>-nitrosoglutathione reductase (GSNOR). Suppressing GSNOR enzymatic activity aggravated Al³⁺ damage to rice and increased the accumulation of RNS. NO treatment altered the expression of proteins associated with cell wall synthesis, cell division and cell structure, calcium signaling and defense responses. On the basis of these results, we propose that NO activates multiple pathways that enhance rice adaptation to Al³⁺ toxicity. Such findings may be applicable to crop engineering to enhance yield and improve stress tolerance