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Summary: Phased, small interfering RNAs (phasiRNAs) are important for plant anther development, especially for male sterility. PhasiRNA biogenesis is dependent on genes like RNA polymerase 6 (RDR6), DICER‐LIKE 4 (DCL4), or DCL5 to produce 21‐ or 24 nucleotide (nt) double‐strand small RNAs. Here, we generated mutants of DCL4, DCL5 and RDR6 using CRISPR/Cas9 system and studied their effects on plant reproductive development and phasiRNA production in wheat. We found that RDR6 mutation caused sever consequence throughout plant development starting from seed germination and the dcl4 mutants grew weaker with thorough male sterility, while dcl5 plants developed normally but exhibited male sterility. Correspondingly, DCL4 and DCL5, respectively, specified 21‐ and 24‐nt phasiRNA biogenesis, while RDR6 contributed to both. Also, the three key genes evolved differently in wheat, with TaDCL5‐A/B becoming non‐functioning and TaRDR6‐A being lost after polyploidization. Furthermore, we found that PHAS genes (phasiRNA precursors) identified via phasiRNAs diverged rapidly among sub‐genomes of polyploid wheat. Despite no similarity being found among phasiRNAs of grasses, their targets were enriched for similar biological functions. In light of the important roles of phasiRNA pathways in gametophyte development, genetic dissection of the function of key genes may help generate male sterile lines suitable for hybrid wheat breeding. [ABSTRACT FROM AUTHOR]

In this study, four grain quality-related genes viz. I pinb i , I waxy i , I ppo i and I psy i , which involved in wheat grain hardness, starch quality and dough colour, respectively, were targeted for genome editing. We envision these new wheat germplasms with improved grain quality can be used as donor parents to improve grain quality of elite wheat cultivars through backcross breeding. Keywords: CRISPR/Cas9; common wheat; pinb; waxy; ppo; psy EN CRISPR/Cas9 common wheat pinb waxy ppo psy 1684 1686 3 09/13/21 20210901 NES 210901 Common wheat supplies vast amounts of dietary carbohydrate and protein for over 60% of world population. CRISPR/Cas9-mediated genome editing for wheat grain quality improvement. [Extracted from the article]

Summary: Increasing grain yields of food cereal crops is a major goal in future sustainable agriculture. We quantitatively analyzed the potential role of arbuscular mycorrhizal (AM) fungi in enhancing grain yields of seven cereal crops with exceptional importance for human nutrition across the globe: corn, wheat, rice, barley, sorghum, millet and oat.We conducted a meta‐analysis for three datasets including both English and Chinese language publications: the 'whole' dataset including both laboratory and field studies (168 articles); the 'field' dataset comprising only field studies (97 studies); and the 'field‐inoculation' dataset including only AM fungal inoculation studies conducted in field conditions (70 articles).We found that the AM fungal effect on grain yield was less pronounced in field and noninoculation studies. AM fungal inoculation in field led to a 16% increase (overall effect) based on the 'field‐inoculation' dataset; this effect was variable (77% trials had positive values), crop‐specific, lower for new cultivars released after 1950 and further modulated by soil pH.Although there are neutral and negative effects of AM fungi on grain yields, we emphasize the importance of integrating AM fungi in sustainable agriculture to increase grain yields of cereal crops. [ABSTRACT FROM AUTHOR]

Keywords: multiplex genome editing; CRISPR/Cas9; common wheat; ribozyme EN multiplex genome editing CRISPR/Cas9 common wheat ribozyme 427 429 3 03/15/21 20210301 NES 210301 Common wheat has a large genome with three subgenomes (A, B and D), making it challenging to create mutations at multiple genomic sites simultaneously. Thus, the tRNA and ribozyme systems are more effective than TRSP, and the ribozyme system appeared to be most robust. Compared with the TRSP system, more plants with over 4 edited sites were identified in the tRNA and ribozyme systems (Figure 1e), and the ribozyme system generated the highest simultaneous editing rates. For I TaNCED1 i , all three vectors exhibited low activity, and the tRNA and ribozyme systems resulted in higher gene editing rates than the TRSP system (Figure 1c). [Extracted from the article]

The CRISPR/Cas9 system has been successfully used in hexaploid wheat. Although it has been reported that the induced mutations can be passed to the next generation, gene editing and transmission patterns in later generations still need to be studied. In this study, we demonstrated that the CRISPR/Cas9 system could achieve efficient mutagenesis in five wheat genes via Agrobacterium-mediated transformation of an sgRNA targeting the D genome, an sgRNA targeting both the A and B homologues and three tri-genome guides targeting the editing of all three homologues. High mutation rates and putative homozygous or biallelic mutations were observed in the T0 plants. The targeted mutations could be stably inherited by the next generation, and the editing efficiency of each mutant line increased significantly across generations. The editing types and inheritance of targeted mutagenesis were similar, which were not related to the targeted subgenome number. The presence of Cas9/sgRNA could cause new mutations in subsequent generations, while mutated lines without Cas9/sgRNA could retain the mutation type. Additionally, off-target mutations were not found in sequences that were highly homologous to the selected sgRNA sequences. Overall, the results suggested that CRISPR/Cas9-induced gene editing via Agrobacterium-mediated transformation plays important roles in wheat genome engineering. [ABSTRACT FROM AUTHOR]

Background: This study aimed to validate the function of CKX gene on grain numbers in wheat. Methods: we constructed and transformed a RNA interference expression vector of TaCKX2.4 in bread wheat line NB1. Southern blotting analysis was used to select transgenic plants with single copy. The expression of TaCKX2.4 gene was estimated by Quantitative real-time PCR (qRT-PCR) analysis. Finally, the relation between expression of TaCKX2.4 gene and grain numbers was validated. Results: Totally, 20 positive independent events were obtained. Homozygous lines from 5 events with a single copy of transformed gene each were selected to evaluate the expression of TaCKX2.4 and grain numbers per spike in T3 generation. Compared with the control NB1, the average grain numbers per spike significantly increased by 12.6%, 8.3%, 6.5% and 5.8% in the T3 lines JW39-3A, JW1-2B, JW1-1A and JW5-1A, respectively. Conclusion: Our study indicated that the expression level of TaCKX2.4 was negatively correlated with the grain number per spike, indicating that the reduced expression of TaCKX2.4 increased grain numbers per spike in wheat. [ABSTRACT FROM AUTHOR]