Mingming Yang

Plant domestication involved prolonged artificial selection that progressively adapted plants to human agricultural practices. This process significantly modified both the genetic diversity and the phenotypic and genotypic characteristics of the domesticated plants, resulting in traits that markedly differ from those of their wild ancestors. At the same time, rhizosphere microorganisms, the second largest gene pool of plants, were also inadvertently altered by domestication through changes in root secretions, nutrient uptake or plant defence responses. In this review, we discuss the effects of domestication on plant rhizosphere microbiota and how plants and microbes interact and co‐evolve during domestication. The effects of these changes are poorly understood and the subject of active ongoing research. The expected knowledge will help to exploit specific microbial communities for the improvement of plant traits and develop microbial‐based management strategies that can be used instead of chemicals to increase plant productivity, reduce environmental pollution and promote the sustainable development of agriculture as a part of the second Green Revolution.

As an important physiological indicator, wheat canopy temperature (CT) can be observed after flowering in an attempt to predict wheat yield and quality. However, the relationship between CT and wheat yield and quality is not clear. In this study, the CT, photosynthetic rate (Pn), filling rate, wheat yield, and wheat quality of 68 wheat lines were measured, in an attempt to establish a connection between CT and yield and quality and accelerate the selection of new varieties. This experiment used an infrared imaging camera to measure the CT of wheat materials planted in the field in 2022. Twenty materials with significant temperature differences were selected for planting in 2023. By comparing the temperature trends in 2022 and 2023, it is believed that materials 4 and 13 were cold-type materials, while materials 3 and 11 were warm-type materials. The main grain filling period of cold-type materials occurs in the middle and late stages of the grain filling period and the Pn and the thousand-grain weights of cold-type materials were higher than those of warm-type materials. Similarly, under continuous rainy conditions, cold-type materials had a higher protein and wet gluten contents, while warm-type materials had higher sedimentation values and shorter formation times.

To investigate the effects of fertilization methods and types on wheat rhizosphere microorganisms, macroelement (N, K) and microelement (Zn) fertilizers were applied on wheat by foliar spraying (FS) and root irrigation (RI) methods in a field experiment. The results indicated that fertilization methods and types can have significant impacts on the diversity and structure of rhizospheric microorganisms in wheat. The application method produced more significant effects than the fertilizer type. RI-N played a more important role in improving the wheat yield and quality and affected the changes in some nitrogen-fixing bacterial communities. Finally, eight strains of bacteria belonging to Pseudomonas azotoformans and P. cedrina showed positive effects on the growth of wheat seedlings. Overall, our study provides a better understanding of the dynamics of wheat rhizosphere microbial communities and their relation to fertilization, yield, and quality, showing that plant growth-promoting rhizobacteria with nitrogen fixing may be a potential approach for more sustainable agriculture production.

The plant core microbiota transmitted by seeds have been demonstrated to exist in seeds and adult plants of several crops for multiple generations. They are closely related to plants and are relatively conserved throughout evolution, domestication, and breeding. These microbiota play a vital role in the early stages of plant growth. However, information about their colonization routes, transmission pathways, and final fate remains fragmentary. This review delves into the concept of these microbiota, their colonization sources, transmission pathways, and how they change throughout plant evolution, domestication, and breeding, as well as their effects on plants, based on relevant literature. Finally, the significant potential of incorporating the practical application of seed-transmitted microbiota into plant microbial breeding is emphasized.

Heat stress is a major abiotic stress that can cause serious losses of a crop. Our previous work identified a gene involved in heat stress tolerance in wheat, TaPLC1-2B. To further investigate its mechanisms, in the present study, TaPLC1-2B RNAi-silenced transgenic wheat and the wild type were comparatively analyzed at both the seedling and adult stages, with or without heat stress, using transcriptome sequencing. A total of 15,549 differentially expressed genes (DEGs) were identified at the adult stage and 20,535 DEGs were detected at the seedling stage. After heat stress, an enrichment of pathways such as phytohormones and mitogen-activated protein kinase signaling was mainly found in the seedling stage, and pathways related to metabolism, glycerophospholipid metabolism, circadian rhythms, and ABC transporter were enriched in the adult stage. Auxin and abscisic acid were downregulated in the seedling stage and vice versa in the adult stage; and the MYB, WRKY, and no apical meristem gene families were downregulated in the seedling stage in response to heat stress and upregulated in the adult stage in response to heat stress. This study deepens our understanding of the mechanisms of TaPLC1-2B in regard to heat stress in wheat at the seedling and adult stages.

As an important type of interplant competition, line-spacing shrinkage and row-spacing expansion (LSRE) can increase the number of tillers and improve resource utilization efficiency in wheat. Wheat tillering is closely related to various phytohormones. However, it is unclear whether LSRE regulates phytohormones and their relationship to tillering and wheat yield. This study evaluated tillering characteristics, phytohormone content in tiller nodes at the pre-winter stage, and grain yield factors for the winter wheat variety Malan1. We used a two-factor randomized block trial design with two sowing spacings of 15 cm (15RS, conventional treatment) and 7.5 cm (7.5RS, LSRE treatment) at the same density and three sowing-date groups (SD1, SD2, and SD3). LSRE significantly promoted wheat tillering and biomass at the pre-winter stage (average increases of 14.5% and 20.9% in the three sowing-date groups, respectively) and shortened the accumulated temperature required for a single tiller. Changes in the levels of phytohormones, including decreased gibberellin and indole acetic acid and increased zeatin riboside and strigolactones, were determined by high-performance liquid chromatography and were shown to be responsible for the tillering process under LSRE treatment in winter wheat. LSRE treatment can improve crop yield by increasing the number of spikes per unit area and grain weight. Our results clarified the changes in tillering and phytohormones content of winter wheat under LSRE treatment and their correlation with grain yield. This study also provides insights into the physiological mechanisms of alleviating inter-plant competition to improve crop yield.

Drought and salt stress are important factors that affect plant growth and development and cause crop yield reductions worldwide. Phospholipase C is a class of enzymes that can hydrolyze phospholipids, and it has been shown to play an important role in plant growth regulation and stress response. We used rice as a model to investigate the function of the wheat TaPI-PLC1-2B gene in salt and drought tolerance. For this purpose, we heterologously expressed the TaPI-PLC1-2B gene in rice and studied the transcriptional differences in transgenic and wide-type rice plants in the presence and absence of drought and salt stress. Our results showed that 2130 and 1759 genes expressed differentially in the TaPI-PLC1-2B overexpression rice line under salt and drought stress, respectively. Gene ontology enrichment results showed that differentially expressed genes (DEGs) were significantly enriched in cellular process, metabolic process, stimulus-response, cell, organelle, catalytic activity, and other functional processes under salt and drought stress. In addition, the Kyoto Encyclopedia of Genes and Genomes pathway analysis showed DEG enrichment in plant-pathogen interaction, phosphoinositol, plant hormones, and other signaling pathways under the two stress treatments. Furthermore, the chromosomal localization of salt and drought stress-responsive DEGs showed a clear distribution pattern on specific rice chromosomes. For instance, the greatest number of drought stress-responsive genes mapped to rice chromosomes 1 and 6. The current analysis has built the basis for future explorations to decipher the TaPI-PLC1-2B-mediated plant stress response mechanism in the relatively challenging wheat system.

Flag leaf senescence is an important determinant of wheat yield, as leaf senescence occurs in a coordinated manner during grain filling. However, the biological process of early senescence of flag leaves post-anthesis is not clear. In this study, early senescence in wheat was investigated using a high-throughput RNA sequencing technique. A total of 4887 differentially expressed genes (DEGs) were identified, and any showing drastic expression changes were then linked to particular biological processes. A hierarchical cluster analysis implied potential relationships between NAC genes and post-anthesis senescence in the flag leaf. In addition, a large set of genes associated with the synthesis; transport; and signaling of multiple phytohormones (JA, ABA, IAA, ET, SA, BR, and CTK) were expressed differentially, and many DEGs related to ABA and IAA were identified. Our results provide insight into the molecular processes taking place during the early senescence of flag leaves, which may provide useful information in improving wheat yield in the future.