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Low temperature is a vital effector of rice at different growth stages. MicroRNAs (miRNAs) play important roles in responding to abiotic and biotic stresses. Here, we confirmed the cold tolerance of Dongxiang common wild rice and explored the miRNAs differentially expressed under cold stress using genome-wide small RNA sequencing. In total, 16 miRNAs, nine upregulated and seven downregulated by cold stress, were characterized in Dongxiang common wild rice, and their target genes were predicted. Additionally, an AgriGO analysis of the target genes revealed that they were enriched in several terms related to cold-stress tolerance, suggesting a complex response mechanism, involving miRNAs, to cold stress in Dongxiang common wild rice. Key words: microRNA, whole genome-wide sequencing, Dongxiang common wild rice, low temperature stress. Le stress du au froid est une contrainte majeure a la croissance normale des plantes, particulierement pour la culture du riz tropical et subtropical, laquelle rencontre souvent des conditions froides au cours de sa croissance, ce qui en reduit le rendement. Les microARN (miARN) jouent des roles cles dans la croissance et le developpement des plantes, particulierement dans la tolerance aux stress biotiques et abiotiques. Dans ce travail, les auteurs ont sequence ARN du riz sauvage commun Dongxiang expose au froid pour identifier 16 miARN dont neuf etaient plus fortement et sept plus faiblement exprimes en reponse au froid. De plus, 45 genes-cibles de ces 16 miARN differentiellement exprimes ont ete predits et, suite a une analyse d'ontologie GO, il a ete montre que ces genes sont significativement enrichis pour des termes lies a la reponse au froid. [Traduit par la Redaction] Mots-cles : microARN, sequencage genomique complet, riz commun Dongxiang, stress de froid., Introduction Low temperature stress is a major restrictive effector of normal plant growth, especially in tropical and subtropical rice crops, which often encounter low temperatures during growth, resulting in yield [...]

Abstract: To understand the genetic characteristics of the traits related to differentiation between cultivated rice and its wild progenitor, genetic factors controlling domestication- and yield-related traits were identified using a [...]

Microbial symbiosis in legumes is achieved through nitrogen-fixing root nodules, and these are important for sustainable agriculture. The molecular mechanisms underlying development of root nodules in polyploid legume crops are largely understudied. Through map-based cloning and QTL-seq approaches, we identified a pair of homoeologous GRAS transcription factor genes, Nodulation Signaling Pathway 2 (AhNSP2-B07 or N b ) and AhNSP2-A08 (N a ), controlling nodulation in cultivated peanut (Arachis hypogaea L.), an allotetraploid legume crop, which exhibited non-Mendelian and Mendelian inheritance, respectively. The segregation of nodulation in the progeny of N a n a n b n b genotypes followed a 3:1 Mendelian ratio, in contrast to the 5:3~1:1 non-Mendelian ratio for n a n a N b n b genotypes. Additionally, a much higher frequency of the n b allele (13%) than the n a allele (4%) exists in the peanut germplasm collection, suggesting that N b is less essential than N a in nodule organogenesis. Our findings reveal the genetic basis of naturally occurred non-nodulating peanut plants, which can be potentially used for nitrogen fixation improvement in peanut. Furthermore, the results have implications for and provide insights into the evolution of homoeologous genes in allopolyploid species. [ABSTRACT FROM AUTHOR]

Photosynthesis and plant architecture are important factors influencing grain yield in rice (Oryza sativa L.). Here, we identified a high-tillering and dwarf 12 (htd12) mutant and analyzed the effects of the HTD12 mutation on these important factors. HTD12 encodes a 15- cis -ζ-carotene isomerase (Z-ISO) belonging to the nitrite and nitric oxide reductase U (NnrU) protein family, as revealed by positional mapping and transformation experiments. Sequence analysis showed that a single nucleotide transition from guanine (G) to adenine (A) in the 3' acceptor site between the first intron and second exon of HTD12 alters its mRNA splicing in htd12 plants, resulting in a 49-amino acid deletion that affects carotenoid biosynthesis and photosynthesis. In addition, compared with the wild type, htd12 had significantly lower concentrations of ent -2'-epi-5-deoxystrigol (epi -5DS), a native strigolactone, in both roots and root exudates, resulting in an obvious increase in tiller number and decrease in plant height. These findings indicate that HTD12, the rice homolog of Z-ISO, regulates chloroplast development and photosynthesis by functioning in carotenoid biosynthesis, and modulates plant architecture by affecting strigolactone concentrations. [ABSTRACT FROM AUTHOR]

Tiller angle, an important component of plant architecture, greatly influences the grain yield of rice (Oryza sativa L.). Here, we identified Tiller Angle Control 4 (TAC4) as a novel regulator of rice tiller angle. TAC4 encodes a plant‐specific, highly conserved nuclear protein. The loss of TAC4 function leads to a significant increase in the tiller angle. TAC4 can regulate rice shoot gravitropism by increasing the indole acetic acid content and affecting the auxin distribution. A sequence analysis revealed that TAC4 has undergone a bottleneck and become fixed in indica cultivars during domestication and improvement. Our findings facilitate an increased understanding of the regulatory mechanisms of tiller angle and also provide a potential gene resource for the improvement of rice plant architecture. [ABSTRACT FROM AUTHOR]