Jinrong Peng , Donald E. Richards , Nigel M. Hartley , George P. Murphy , Katrien M. Devos , John E. Flintham , James Beales , Leslie J. Fish , Anthony J. Worland , Fatima Pelica , Duraialagaraja Sudhakar , Paul Christou , John W. Snape , Michael D. Gale , Nicholas P. Harberd <<<

World wheat grain yields increased substantially in the 1960s and 1970s because farmers rapidly adopted the new varieties and cultivation methods of the so-called ‘green revolution’1,2,3,4. The new varieties are shorter, increase grain yield at the expense of straw biomass, and are more resistant to damage by wind and rain3,4. These wheats are short because they respond abnormally to the plant growth hormone gibberellin. This reduced response to gibberellin is conferred by mutant dwarfing alleles at one of two Reduced height-1 (Rht-B1 and Rht-D1) loci4,5. Here we show that Rht-B1/Rht-D1 and maize dwarf-8 (d8)6,7 are orthologues of the Arabidopsis Gibberellin Insensitive (GAI) gene8,9. These genes encode proteins that resemble nuclear transcription factors and contain an SH2-like10 domain, indicating that phosphotyrosine may participate in gibberellin signalling. Six different orthologous dwarfing mutant alleles encode proteins that are altered in a conserved amino-terminal gibberellin signalling domain. Transgenic rice plants containing a mutant GAI allele give reduced responses to gibberellin and are dwarfed, indicating that mutant GAI orthologues could be used to increase yield in a wide range of crop species. <<<

As a major event in human civilization, wild plants were successfully domesticated to be crops, largely owing to continuing artificial selection. Here, we summarize new discoveries made during the past decade in crop domestication and breeding. The construction of crop genome maps and the functional characterization of numerous trait genes provide foundational information. Approaches to read, interpret, and write complex genetic information are being leveraged in many plants for highly efficient de novo or re-domestication. Understanding the underlying mechanisms of crop microevolution and applying the knowledge to agricultural productions will give possible solutions for future challenges in food security. <<<

Flowering plants alternate between multicellular haploid (gametophyte) and diploid (sporophyte) generations. Pollen actively transcribes its haploid genome, providing phenotypic diversity even among pollen grains from a single plant. In this study, we used allele-specific RNA sequencing of single pollen precursors to follow the shift to haploid expression in maize pollen. We observed widespread biallelic expression for 11 days after meiosis, indicating that transcripts synthesized by the diploid sporophyte persist long into the haploid phase. Subsequently, there was a rapid and global conversion to monoallelic expression at pollen mitosis I, driven by active new transcription from the haploid genome. Genes showed evidence of increased purifying selection if they were expressed after (but not before) pollen mitosis I. This work establishes the timing during which haploid selection may act in pollen. <<<

Yongqiang Liu, Hongru Wang, Zhimin Jiang, Wei Wang, Ruineng Xu, Qihui Wang, Zhihua Zhang, Aifu Li, Yan Liang, Shujun Ou, Xiujie Liu, Shouyun Cao, Hongning Tong, Yonghong Wang, Feng Zhou, Hong Liao, Bin Hu, Chengcai Chu <<<

The intensive application of inorganic nitrogen underlies marked increases in crop production, but imposes detrimental effects on ecosystems: it is therefore crucial for future sustainable agriculture to improve the nitrogen-use efficiency of crop plants. Here we report the genetic basis of nitrogen-use efficiency associated with adaptation to local soils in rice (Oryza sativa L.). Using a panel of diverse rice germplasm collected from different ecogeographical regions, we performed a genome-wide association study on the tillering response to nitrogen-the trait that is most closely correlated with nitrogen-use efficiency in rice-and identified OsTCP19 as a modulator of this tillering response through its transcriptional response to nitrogen and its targeting to the tiller-promoting gene DWARF AND LOW-TILLERING (DLT). A 29-bp insertion and/or deletion in the OsTCP19 promoter confers a differential transcriptional response and variation in the tillering response to nitrogen among rice varieties. The allele of OsTCP19 associated with a high tillering response to nitrogen is prevalent in wild rice populations, but has largely been lost in modern cultivars: this loss correlates with increased local soil nitrogen content, which suggests that it might have contributed to geographical adaptation in rice. Introgression of the allele associated with a high tillering response into modern rice cultivars boosts grain yield and nitrogen-use efficiency under low or moderate levels of nitrogen, which demonstrates substantial potential for rice breeding and the amelioration of negative environment effects by reducing the application of nitrogen to crops. <<<