Search

Abstract: A five-year experiment with Free Air Temperature Increase facility was conducted to investigate the actual responses of winter wheat phenophase and yield to warming in Yangtze Delta Plain, China. Air temperature increase of around 1.5°C in wheat canopy advanced crop phenophases significantly, leading to a reduction in length of the entire growth period by 10 days (P <0.05). This reduction was mainly found in the length of pre-anthesis phase, while the length of post-anthesis phase was prolonged slightly. Warming increased grain yield by 16.3% (P <0.05) whereas no significant effects were found on the aboveground biomass. Warming tended to increase the numbers of productive spike and filled grain and the harvest index. The areas of flag leaf and total green leaf at anthesis and the 1000-grain weight were 36.0, 19.2 and 5.9% higher in the warmed plots than the un-warmed control (P <0.05), respectively. Warming stimulated the filling rate of inferior grain (P <0.05), while the rate of superior grain stayed almost unchanged. The above evidences suggest that anticipated warming may facilitate winter wheat production in East China. [Copyright &y& Elsevier]

The chloroplast is an important organelle that performs photosynthesis as well as biosynthesis and storage of many metabolites. Aminoacyl-tRNA synthetases (aaRSs) are key enzymes in protein synthesis. However, the relationship between chloroplast development and aaRSs still remains unclear. In this study, we isolated a rice albino 1 (ra1) mutant through methane sulfonate (EMS) mutagenesis of rice japonica cultivar Ningjing 4 (Oryza sativa L.), which displayed albinic leaves in seedling stage due to abnormal chloroplast development. Compared with wild type (WT), ra1 showed significantly decreased levels of chlorophylls (Chl) and carotenoids (Car) in 2-week-old seedlings, which also showed obvious plastidic structural defects including abnormal thylakoid membrane structures and more osmiophilic particles. These defects caused albino phenotypes in seedlings. Map-based cloning revealed that RA1 gene encodes a glycyl-tRNA synthetase (GlyRS), which was confirmed by genetic complementation and knockout by Crispr/Cas9 technology. Sequence analysis showed that a single base mutation (T to A) occurred in the sixth exon of RA1 and resulted in a change from Isoleucine (Ile) to Lysine (Lys). Real-time PCR analyses showed that RA1 expression levels were constitutive in most tissues, but most abundant in the leaves and stems. By transient expression in Nicotiana benthamiana , we found that RA1 protein was localized in the chloroplast. Expression levels of chlorophyll biosynthesis and plastid development related genes were disordered in the ra1 mutant. RNA analysis revealed biogenesis of chloroplast rRNAs was abnormal in ra1. Meanwhile, western blotting showed that synthesis of proteins associated with plastid development was significantly repressed. These results suggest that RA1 is involved in early chloroplast development and establishment of the plastidic ribosome system in rice. • RA1 is a novel gene controlling chlorophyll synthesis and the ribosome system. • Absence of aminoacyl-tRNA synthetases lead to plastid developmental disorders. • Biosynthesis of plastidic ribosomes is severely impaired in the ra1 mutant. • RA1 protein is targeted to the chloroplast. [ABSTRACT FROM AUTHOR]

Great attentions have been taken to the effects of climatic warming on crop production, however, fewer were known about the actual impacts of nighttime warming under different cropping systems. Therefore, a three-year field experiment with a passive nighttime warming (PNW) facility and a one-year field experiment with free air temperature increase (FATI) facility were conducted in major Chinese rice cropping systems. Four-year field observations from different rice cropping systems all showed that nighttime warming less than 1.0 °C could shorten the length of crop pre-flowering phase period while prolonged the length of post-flowering phase period, resulting in insignificant reduction in the length of crop entire growth period. The temperature increase caused significant increments in grain yields by 16.2, 12.7 and 12.0% for late rice in the rice–rice cropping system, wheat in the rice-wheat cropping system and rice in the single rice cropping system, respectively. However, this warming declined grain yields significantly by 4.5 and 6.5% for early rice in the rice–rice cropping system and rice in the rice-wheat cropping system, respectively. Since warming-induced yield reduction was less than warming-induced increment in each cropping system, the annual yields was higher in the warmed plots than the non-warmed under all systems. Our findings can provide important references to cropping system adjustment for coping with global warming in China and other regions. [ABSTRACT FROM AUTHOR]

Seed dormancy and germination in rice (Oryza sativa L.) are complex and important agronomic traits that involve a number of physiological processes and energy. A mutant named h470 selected from a60Co-radiated indica cultivar N22 population had weakened dormancy that was insensitive to Gibberellin (GA) and Abscisic acid (ABA). The levels of GA 4 and ABA were higher in h470 than in wild-type (WT) plants. The gene controlling seed dormancy in h470 was cloned by mut-map and transgenesis and confirmed to encode an ADP-glucose transporter protein. A 1 bp deletion in Os02g0202400 (OsBT1) caused the weaker seed dormancy in h470. Metabolomics analyses showed that most sugar components were higher in h470 seeds than the wild type. The mutation in h470 affected glycometabolism. • We identified a new allele of OsBT1 regulating seed dormancy in rice. • The germination phenotype of h470 was not regulated by GA or ABA. • The OsBT1 protein regulates seed dormancy through the glycometabolism pathway. [ABSTRACT FROM AUTHOR]

Understanding the actual impacts of climatic warming on winter-sown wheat production will benefit cultivar breeding efforts and agronomic innovations and may help to improve food security. Therefore, we conducted a comprehensive study across the main Chinese winter wheat cropping regions, comprising field warming experiments at four locations and an analysis of 36 years of winter wheat yield data. In the field warming experiments, an increase of 1.0 °C in nighttime temperature enhanced wheat yield by 10.1% on average ( P < 0.05 ). Warming-induced enhancement of 1000-grain weight explained most of these yield increases. Warming shortened the length of pre-flowering phase by 5.4 days, while it prolonged the length of post-flowering phase by 3.8 days. Grain yield increases with warming were similar across experimental sites, even though warming-induced changes in the length of growth periods decreased with increasing ambient temperature. Our analysis of the historical data set was consistent with our field warming experiments; between 1980 and 2015, the major Chinese cropping regions experienced significant warming, especially in daily minimum temperature. Across the historical data set, daily minimum temperature was positively correlated with wheat yield (142.0 kg ha −1 °C −1 ). Our findings are inconsistent with previous reports of yield decreases with warming and may help to inform policy decisions and agronomic innovations of Chinese wheat production to better cope with future climate warming. [ABSTRACT FROM AUTHOR]

Abstract: Crop model projections and historical data analyses have shown that global warming may cause serious decrease in crop productivity, however, many uncertainities remain on the impact quantification due to the unclear understanding of actual crop response. Therefore, we performed a three-year field warming experiment with free air temperature increase (FATI) facility to investigate the actual response of midseason rice growth in East China. There were four treatments (AW: all-day warming; DW: daytime warming; NW: nighttime warming; CK: ambient control) with three replicates. This FATI facility presented a good simulation of the local air temperature pattern with an increase in the daily mean temperature of about 1.1–2.0°C during rice whole growth duration compared to the ambient control. Warming shortened the pre-heading phase respectively by 3.3d, 1.7d and 2.0d in the AW, DW and NW plots, while the post-heading phase stayed almost unchanged. During the three years, warming slightly decreased the aboveground biomass by an average of 9.1%, 10.3% and 3.3%, and the grain yield by an average of 0.9%, 6.4% and 6.1% in the AW, DW and NW plots, respectively. Warming tended to decrease rice photosynthesis rate and stimulate the nighttime respiration rate. It also enlarged the flag leaf area and increased its chlorophyll content. No significant difference and interaction in the actual response of rice growth were found between the warming regimes. The above evidences suggest that the expected warming less than 2.0°C may not cause significant decrease in rice productivity in East China. [Copyright &y& Elsevier]