Complex biological processes such as plant growth and development are often under the control of transcription factors that regulate the expression of large sets of genes and activate subordinate transcription factors in a cascade-like fashion. Here, by screening candidate photosynthesis-related transcription factors in rice, we identified a DREB (Dehydration Responsive Element Binding) family member, OsDREB1C, in which expression is induced by both light and low nitrogen status. We show that OsDREB1C drives functionally diverse transcriptional programs determining photosynthetic capacity, nitrogen utilization, and flowering time. Field trials with OsDREB1C -overexpressing rice revealed yield increases of 41.3 to 68.3% and, in addition, shortened growth duration, improved nitrogen use efficiency, and promoted efficient resource allocation, thus providing a strategy toward achieving much-needed increases in agricultural productivity.

Key message: We found GmNAC06 plays an important role in salt stress responses through the phenotypic, physiological and molecular analyses of OE, VC, and Mutant composite soybean. Salinization affects 20% of all cultivated land worldwide because of the high salinity of irrigation water and the excessive use of water, and this amount is increasing daily. NAC (NAM, ATAF, and CUC) have been found to be involved in salt stress. In this study, a soybean NAC gene, GmNAC06 (Glyma06g21020.1), was cloned and functionally characterized. The results of expression analysis suggested that salt stress could influence the expression level of GmNAC06. The subcellular localization analysis results suggested that GmNAC06 may function as a transcription factor. Under salt stress, the overexpression technology combined with CRISPR-Cas9 system found that GmNAC06 could cause the accumulation of proline and glycine betaine to alleviate or avoid the negative effects of ROS; similarly, it could control the Na⁺/K⁺ ratios in hairy roots to maintain ionic homeostasis. The fresh weight of the transgenic hairy roots and the histochemical ROS staining of wild leaves suggested that transgenic hairy roots influence the function of wild leaves under salt stress conditions. Moreover, the expression levels of GmUBC2 and GmHKT1 were higher in the GmNAC06 hairy roots than in the control. Thus, the overexpression of GmNAC06 in hairy roots notably causes an entire composite plant to exhibit salt tolerance. The phenotype of composite soybean plants and transgenic Arabidopsis plants suggest that GmNAC06 plays a role in response to salt stress and could be useful in generating salt tolerant transgenic crops.

CRISPR/Cas9‐based base editor (BE) technology that enables precise base‐editing has been developed and applied in several plant species, including Arabidopsis, rice, wheat, maize, tomato and cotton. However, it is not clear whether base editing will work in allotetraploid oilseed rape (Brassica napus L.). In this study, we successfully established a base‐editing system that can efficiently introduce C to T conversion in sgRNA targets in oilseed rape. BnALS (acetolactate synthase) gene, the target site of several important herbicides was closed edited at position P197 by the BE system, conferred tribenuron‐methyl resistant to oilseed rape. The base editing efficiency for BnALS1 was about 1.8% (4/217). Homozygous mutants without exogenous T‐DNA could be obtained in T1 generation. No off‐target effect was detected in the mutated plants. In addition, in order to easily discriminate between the WT and the P197S mutant alleles, allele‐specific PCR markers were developed. The BE would be a very useful tool for gene function study and precision molecular breeding in oilseed rape. The P197S substitution in BnALS1 generates a novel herbicide‐resistant mutant in oilseed rape, and the transgene‐free homozygous mutant with its allele‐specific markers could be used for breeding herbicide resistance and thus might facilitate weed management in oilseed rape production.