Zhengang Ru

Fusarium head blight (FHB), caused by Fusarium graminearum (F. graminearum), has become one of the most devastating wheat diseases, severely impacting both grain yield and quality. The resistance gene TaHis (encoding a histidine-rich calcium-binding protein), located at the major FHB resistance locus Fhb1, has been demonstrated to confer FHB resistance in wheat, although its underlying mechanism remains unclear. In this study, we screened a wheat yeast two-hybrid (Y2H) library and identified TaU11/U12-35K, a core component of the U12-type spliceosome (U11/U12 small nuclear ribonucleoprotein), as a novel interacting partner of TaHis. Their physical interaction was further confirmed by both Y2H and bimolecular fluorescence complementation assays. Barley stripe mosaic virus-induced gene silencing (BSMV-VIGS)-mediated knockdown of TaU11/U12-35K significantly enhanced FHB resistance in both resistant (Bainong 4299) and susceptible (Bainong 5819) cultivars compared to controls. Expression profiling revealed that TaU11/U12-35K was significantly downregulated upon F. graminearum infection in both cultivars, with consistently lower basal expression levels in Bainong 4299, suggesting a negative correlation between TaU11/U12-35K expression and FHB resistance. Collectively, our results demonstrate that TaU11/U12-35K physically interacts with TaHis and functions as a negative regulator of FHB resistance. This study provides new insights into the molecular mechanism of TaHis-mediated FHB resistance in wheat.

Increasing wheat (Triticum aestivum L.) planting density is the most effective production management method for increasing yields; however, excessive crop populations under high planting densities may experience elevated risk of stem lodging. We conducted this study to assess the relationship between reduced lodging and increased yield, investigate the effects of planting density on wheat population structure, stem strength, and material transport, and provide a basis for rationale planting densities. The experiments were carried out using a split-plot design with three replicates. The main plots contained two wheat varieties: Bainong 5819 (BN5819) and Bainong 4199 (BN4199), and the sub-plots contained four planting density treatments: 90 × 10⁴ plants/ha (D1), 180 × 10⁴ plants/ha (D2), 270 × 10⁴ plants/ha (D3), and 360 × 10⁴ plants/ha (D4). A two-year field trial was conducted in 2021–2023. The relationships between population structure characteristics, changes in stem strength, activation, and retransport of stem material after anthesis, and achievement of high and stable yields were investigated at the different planting densities. When the planting density of wheat increased from D1 to D4 treatment, the activity of fructan hydrolase was significantly increased. Compared with D1 treatment, the highest activity of fructan hydrolase was increased by 457.47 μg/h/g under D4 treatment. At the same time, the increase of density also increased the contribution rate of dry matter accumulation (CDMA) to grain after anthesis increased, with the highest increase in CDMA at 33.67%, which significantly reduced stem strength. Correlation analysis revealed a significant negative association between CDMA and stem strength. Specifically, CDMA levels were significantly lower with the D3 treatment than the D4 treatment, while stem strength remained higher after anthesis as an adaptive response to mitigate lodging risk. Stem storage compounds can promote grain filling and a weight increase in inferior grains. The number of spikes per unit area increased significantly with increasing planting density, but the number of grains per spike and 1000-grain weight decreased significantly. In two years, the number of spikes in D3 treatment increased by a maximum of 211.67 × 10⁴ ha⁻¹ and 99.17 × 10⁴ ha⁻¹, respectively, compared to D1 and D2 treatments. The number of grains per spike was significantly higher than that of D4 treatment, the highest being 3.68 grains. Therefore, in the North China Plain with suitable water, fertilizer, and temperature, the sowing density of 270 × 10⁴ plants/ha established population structure, significantly reduced CDMA, maintained post-anthesis stem strength, enhanced resilience of stems against post-anthesis lodging, and resulted in high yields by stabilizing the number of grains per spike and increasing the number of wheat spikes.

Nitrogen fertilizer input is the main determinant of wheat yield, and heavy nitrogen fertilizer application causes serious environmental pollution. It is important to understand the genetic response mechanism of wheat to nitrogen and select wheat germplasm with high nitrogen efficiency. In this study, 204 wheat species were used to conduct genome-wide association analysis. Nine phenotypic characteristics were obtained at the seedling stage in hydroponic cultures under low-, normal, and high-nitrogen conditions. A total of 765 significant loci were detected, including 438, 261, and 408 single nucleotide polymorphisms (SNPs) associated with high-, normal, and low-nitrogen conditions, respectively. Among these, 14 SNPs were identified under three conditions, for example, AX-10887638 and AX-94875830, which control shoot length and root–shoot ratio on chromosomes 6A and 6D, respectively. Additionally, 39 SNPs were pleiotropic for multiple traits. Further functional analysis of the genes near the 39 SNPs shows that some candidate genes play key roles in encoding proteins/enzymes, such as transporters, hydrolases, peroxidases, glycosyltransferases, oxidoreductases, acyltransferases, disease-resistant proteins, ubiquitin ligases, and sucrose synthetases. Our results can potentially be used to develop low-nitrogen-tolerant species using marker-assisted selection and provide a theoretical basis for breeding efficient nitrogen-using wheat species.

Powdery mildew and leaf rust are wheat diseases against which Th. Ponticum contains genes that confer resistance. Here, an elite wheat-Th. ponticum disomic substitution line DS5Ag(5D), which confers high resistance to both diseases, was developed and characterized in the Bainong Aikang58 (AK58) background, using genomic in situ hybridization (GISH), oligo-nucleotide probe multiplex fluorescence in situ hybridization (FISH) and molecular markers. There were 27 5Ag chromosome-specific molecular markers, of which 22 were co-dominant, confirming chromosome identification and SNP markers from the wheat 660 K SNP chip and providing molecular tools for tagging the alien chromosome. DS5Ag(5D) had higher resistance than its common wheat parents AK58 to powdery mildew throughout the growth period and leaf rust at the adult stage. Based on the resistance evaluation of DS5Ag(5D) and its parents, segregation analysis using five F₅ populations with different sensitive wheat backgrounds showed that the resistance genes mapped to 5Ag confer stable effects on the two diseases in different backgrounds. Resistance spectrum analysis combined with diagnostic marker detection of known resistance genes of Th. ponticum revealed that 5Ag contained two novel genes, Pm5Ag and Lr5Ag, which conferred resistance to powdery mildew and leaf rust, respectively. New elite germplasm and molecular markers for breeding wheat with powdery mildew and leaf rust resistance are provided in this study.

Optimizing supplemental irrigation (SI) measures and enhancing stem lodging resistance can be the keys to achieving a high and stable yield and high efficiency in wheat. The experiment was established as a two-factor field trial in 2018–2020. We used four SI combinations at different stages: rain-fed (T0), SI at jointing (T1), SI at jointing + anthesis (T2), and SI at regreening + jointing + anthesis (T3) with ‘Bainong4199’ (BN4199) and ‘Zhoumai18’ (ZM18) as experimental materials. We researched the effects of different SI combinations on the stem characteristics, stem vigor, grain filling, and yield of winter wheat. The results suggest that the basal internode at the anthesis stage grew with the increase in SI amount, but the stem fracture resistance of T1 and T2 was higher than that of T0 and T3. As grain filling continued, the lodging index increased and stem vigor decreased. In comparison with T3, the average stem lodging index of T2 decreased by 21.92% for ‘BN4199’ and 36.63% for ‘ZM18’, but the WUE increased by 29.76% and 14.92%, respectively. The grain yield increased with the increase in irrigation times during the growth period; there was no significant difference between T2 and T3 in 2018–2019. In a biennial comparison, the grain yield of all treatments in 2019–2020 was significantly lower than those in 2018–2019, and the grain yield of ‘ZM 18’ was lower than that of ‘BN 4199’. Correlation analysis displayed that there were significant positive correlations between post-anthesis stem vigor and the dry matter contribution rate of post-anthesis to grains and between the grain filling rate at 21–28 days after anthesis (DAA) and stem strength at 30 DAA. In summary, selecting a high-yield lodging-resistant wheat variety with SI at jointing and anthesis was beneficial for forming strong stems and maintaining higher stem vigor at the later growth stage for grain filling, which reduced lodging risk and ensured high yield and high WUE.

Changes in rhizosphere pH play an important role in wheat growth. To investigate the relationship between changes in rhizosphere pH and the growth of winter wheat roots and to explore the regulatory mechanism of acid and alkali resistance in winter wheat roots, the semi-winter wheat varieties Aikang 58 (AK58) and Bainong 4199 (BN4199) were used as materials for hydroponic experiments. Three pH levels (4.0, 6.5, and 9.0, with 6.5 as control) were applied during the wheat seedling stage. The results showed that the shoot and root biomass of the plants significantly decreased compared with the control under acid-base stress, with a more significant decrease with acid stress than alkali stress. Compared with the control, the root/shoot ratio increased under alkali stress and decreased under acid stress. The wheat root system showed H ⁺ net efflux at pH 6.5 and 9.0, and the H ⁺ net efflux rate at pH 4.0 was significantly lower than the control. The root activity of wheat was higher than the control at pH 9.0 and lower at pH4.0. The change of root pH was showed pH 4.0 < pH 6.5 < pH 9.0. Correlation analysis showed that changes in H ⁺ net flux were significantly positively correlated to root activity and root pH. The H ⁺ efflux rate and root activity of BN4199 were highe r than AK58 under acid and alkali stress, and the root/shoot ratio was relatively high, indicating strong acid and alkali resistance. We conclude that wheat could adapt to poor acid-base environments by adjusting root H ⁺ net flux, and in practice, the root/shoot ratio could be used as index for the rapid determination of acid-base tolerance in wheat at the seedling stage.

Winter wheat (Triticum aestivum L.) production in the North China Plain (NCP) is threatened by wheat lodging. Therefore, enhancing plant lodging resistance by improving stem quality traits is crucial to maintaining high stable yields of winter wheat. A consecutive 7-year field experiment was conducted to study the effects of stem traits on lodging resistance and the yield of four winter wheat cultivars (Bainong 418, Aikang 58, Wenmai 6 and Zhoumai 18). The results indicated that rainfall is often accompanied by strong winds that can cause lodging in the field. Stalk bending strength and wall thickness of the second internode showed significant negative correlations with lodging index, and a higher lodging index indicated increased lodging risk, which, in turn, could seriously affect the grain yield of wheat. Significant regression relationships were observed between lodging index and population lodging resistance strength, as measured using a crop lodging resistance electronic measuring device. Statistical analysis revealed that yield components and the grain yield of Bainong 418 were higher than those of the other cultivars; there was no significant difference between Bainong 418 and Aikang 58 in lodging index, stalk bending strength or single-stalk and population lodging resistance strengths at anthesis and the middle filling stages, but the mean plant height of Bainong 418 was significantly higher than that of Aikang 58. These results provide a new and reliable method for assessing lodging resistance capacity and indicate that greater lodging resistance, as determined by simultaneously considering plant height and basal stem strength, is an important way to achieve high, stable yield in winter wheat.