This study assessed the responses of wild-type (WT) and transgenic Arabidopsis expressing seven combinations of maize (Zea mays) genes phosphoenolpyruvate carboxylase (pepc), pyruvate phosphate dikinase (ppdk), and NADP-malic enzyme (nadp-me) to high light. Our results showed that the net CO₂ assimilation rate (P_n) and shoot dry weight of four of the transgenic Arabidopsis genotypes were significantly different from those of WT under high-light treatment, being in the order of Zmpepc+Zmppdk+Zmnadp-me (PC-K-M) > Zmpepc+Zmppdk (PC-K) > Zmpepc (PC), Zmpepc+Zmnadp-me (PC-M) > WT. The other genotypes did not differ from WT. This indicated that Zmpepc was essential for maintaining high photosynthetic performance under high light, Zmppdk had a positive synergistic effect on Zmpepc, and the combination of all three genes had the greatest synergistic effect. These four genotypes also maintained higher photosystem II (PSII) activity (K-phase, J-phase, RC/CSm), electron transfer capacity (J-phase), and photochemical efficiency (TRo/ABS), and accumulated less reactive oxygen species (O₂·⁻, H₂O₂) and suffered less damage to the membrane system (MDA) than WT under high light. Collectively, PC, PC-K, PC-M, and PC-K-M used most of the absorbed energy for CO₂ assimilation through a significantly higher P_n, which reduced the generation of excess electrons in the photosynthetic apparatus, thereby reducing damage to the membrane system and PSII. This ultimately resulted in improved high-light tolerance. P_n was the main reason for the significant difference in the high-light tolerance of the four genotypes. Joint expression of the three maize genes may be of great value in the genetic improvement of high-light tolerance in C₃ crops.

The Huanghuai winter wheat region, China’s primary wheat-producing area, predominantly cultivates white-grained wheat. Pre-harvest sprouting (PHS) significantly impacts yield and quality, making the breeding of PHS-resistant varieties crucial for ensuring China’s wheat production security. This study evaluated the PHS rate of 344 white-grained wheat varieties over two consecutive growing seasons (2022/2023 and 2023/2024). Furthermore, it analyzed the effects of allelic variations and their combinations in six genes (Tamyb10, TaDFR, TaMKK3-A, TaGASR34, Tasdr, and TaMFT) on PHS resistance. Results revealed average PHS rates of 66.1% and 64.4% for the two growing seasons, with coefficients of variation of 39.1% and 40.2%, respectively, and a narrow-sense heritability of 0.72. These findings indicate substantial genetic variation and relatively high genetic stability within the tested materials. Among the six molecular markers examined, the superior haplotype GS34-7Bb exhibited the lowest average PHS rate (41.9%) over two growing seasons, demonstrating the strongest PHS resistance. Analysis of different haplotype combinations identified two advantageous genotypes for PHS resistance in white-grained wheat: TaMKK3-Ab + GS34-7Bb + Tasdr-2Aa + TaMFT-A1b (average PHS rate: 20.8%) and TaMKK3-Ab + GS34-7Bb + Tasdr-2Ab + TaMFT-A1b (average PHS rate: 34.2%). Notably, the distribution frequency of superior haplotypes of PHS-related genes and these two advantageous haplotype combinations showed varying degrees of decline over time.

Although wheat cultivars and yields in Henan Province have improved continuously, there have been no systematic reports on breeding improvement in recent decades. This study aims to elucidate the genetic basis of these wheat cultivars and summarize their breeding advances across four breeding periods. A total of 351 landraces and 265 cultivars from Henan Province were used in selective sweep studies and planted at five locations within the province in 2016 − 2017, 2017 − 2018, and 2018 − 2019 for genome-wide association studies. Candidate genes were identified through differential expression, Gene Ontology (GO) annotation, gene homology, and haplotype analyses. The results demonstrated that 263 known genes with selection signals were associated with yield, quality, and resistance traits. Of the quantitative trait loci identified, 51 genes had been previously reported, whereas 252 genes were novel candidates; among these, 80 genes and 50 loci contributed to the improvement of 12 traits, such as plant height. Twelve key candidate genes were verified by quantitative reverse transcription PCR (qRT-PCR). Superior haplotypes of 24 and 164 genes, respectively, explain cultivar climate adaptation and are available for future breeding. Conversely, analyses of superior haplotypes in cultivars from the 2000s onward suggest that parental selection should consider a broader range of germplasm resources, rather than just recent accessions. The transmission of superior haplotypes in four varietal pedigrees revealed the pyramiding in elite cultivars. This study provides a genetic basis for wheat improvement and offers guidance for future genetic improvement.

Breeding wheat varieties with a high nitrogen use efficiency (NUE) reduces both production costs and threats to the ecological environment. Here, using candidate-gene and genome-wide association studies, we identify TaNPF7.6-A1 as a positive regulator of NUE in wheat. A widely conserved polymorphism in the coding region of TaNPF7.6-A1 produces allele TaNPF7.6-A1^mod with a higher transcription level and nitrate transport activity than TaNPF7.6-A1^lan, resulting in a greater NUE. We also reveal the mechanism by which TaEIL3-TaJAZ1-TaNPF7.6-A1 regulates NUE in wheat. TaNPF7.6-A1^mod interacts more strongly with TaJAZ1 than TaNPF7.6-A1^lan and promotes the retention of nuclear-localized TaJAZ1 in the cytoplasm. TaJAZ1 interacts with TaEIL3 and represses TaEIL3, binding to the TaNPF7.6-A1^mod promoter, influencing allele expression and causing phenotypic differences. TaNPF7.6-A1^mod also shows significant geographical distribution aggregation globally and undergoes continuous positive selection during the breeding process. Overall, this study provides molecular and evolutionary insights into the regulation of NUE.

Despite the continuous improvement of wheat cultivars in Henan Province, the largest Chinese wheat-producing area, there have been no reports of studies on their breeding advances in the past decades. This study aims to elucidate their genetic basis and breeding advances. A total of 351 landraces and 265 cultivars in Henan Province were employed in selective sweep studies and genome-wide association studies. All the wheat accessions were planted in five locations in Henan Province in 2016−2017, 2017−2018 and 2018−2019. Candidate genes were identified through differential expression, GO annotation, gene homology, and haplotype analyses. Breeding advances were summarized based on four breeding periods (1950s, 1960s−1970s, 1980s−1990s, and post−2000s) of all 265 cultivars. The results demonstrated that 263 known genes with selection signals were found to be associated with important traits. Around the detected quantitative trait loci, 51 genes had been previously reported, while 252 genes were identified as candidate genes. Of the 303 genes and loci identified, 80 genes and 50 loci contributed to the improvement of 12 traits like plant height, and 12 key candidate genes was verified by qRT-PCR, while superior haplotypes of 24 genes explained cultivar climate adaptation. The superior haplotypes of 164 genes are available for future breeding. Transmission of superior haplotypes in four varietal pedigrees revealed pyramiding of superior haplotypes in elite cultivars. The analysis of post−2000 cultivars suggests a broader range of germplasm resources should be considered in parental selection than only recent accessions. This study provides a genetic basis and guide for wheat improvement.

Breeding wheat varieties with high nitrogen use efficiency (NUE) effectively reduces threats to the ecological environment and production costs. Here, this study identifies TaNPF7.6-A1 as a positive regulator of NUE in wheat through candidate-gene and genome-wide association studies. A widely conserved polymorphism in the coding region of TaNPF7.6-A1 produces an allele, TaNPF7.6-A1mod, that has a higher transcriptional level and nitrate transport activity, resulting in greater NUE than TaNPF7.6-A1lan. We also discovered a novel mechanism of TaEIL3-TaJAZ1-TaNPF7.6-A1 regulating NUE in wheat: TaNPF7.6-A1mod interacts more strongly with TaJAZ1 and promotes the retention of nuclear-localized TaJAZ1 in the cytoplasm than TaNPF7.6-A1lan does. TaJAZ1 interact with TaEIL3 and repress TaEIL3 binding to the TaNPF7.6-A1mod promoter, thereby influencing alleles’ expression and causing phenotypic differences. TaNPF7.6-A1mod also shows significant geographical distribution aggregation globally and has undergone continuous positive selection during the breeding process. Overall, this study provides molecular and evolutionary insights into the regulation of NUE.