Plants exhibit striking developmental plasticity, driven by stem cell populations within meristematic tissues such as the shoot apical meristem (SAM). While the genetic networks governing stem cell homeostasis are well-characterized, recent studies reveal that the SAM also functions as an active environmental sensor to modulate growth plasticity. This Tansley review synthesizes advances in how the SAM perceives and integrates key environmental signals - including light, temperature, oxygen, and humidity - to direct adaptive growth. We detail the molecular mechanisms, such as photoreceptor-mediated activation, thermal resilience pathways, hypoxia sensing, hydraulic dynamics, and mechanical signalling, that regulate stem cell activity. Furthermore, we explore how these environmental cues couple with developmental programs to fine-tune meristem function and organogenesis. By drawing parallels to the environmental regulation of root meristem development, we highlight conserved sensing and signalling modules within meristematic tissues that influence plant growth plasticity. Examining this interplay both in shoot and in root meristems, from evolutionary and applied perspectives, underscores how environmental responsiveness of stem cell niches regulates plant adaptation, informing strategies for engineering climate-resilient crops.
Yi-Min Zhu, Han Han, Weibing Yang· New Phytologist· 0 citations
Drought severely limits global wheat production, and plants can mitigate this stress by recruiting beneficial rhizosphere microbiomes. However, the role of host genotype in shaping this recruitment and influencing microbial inoculant efficacy is poorly understood. Here, we aimed to elucidate the interplay among host genotype, drought stress, and inoculation with Trichoderma citrinoviride. A factorial pot experiment investigated the responses of two wheat genotypes (JN 14-95, constitutively drought-tolerant; JN 72, drought-responsive) to water regimes and inoculation with T. citrinoviride. Metagenomic analysis was performed to characterize rhizosphere bacterial community structure and functional potential. Host genotype was the primary driver of bacterial community structure (42.3% of variation), exceeding water stress (23.8%) and inoculation (11.5%). JN 14-95 adopted a “physiological autonomy” strategy with constitutive high root-to-shoot ratio and inferred enrichment of auxin and SOD biosynthesis genes. JN 72 employed a “microbial outsourcing” strategy, enriching beneficial bacteria (Pseudomonas, Bacillus, Streptomyces) and showing inferred enrichment of central carbon metabolism genes. T. citrinoviride amplified these genotype-specific responses, increasing the total dry matter by 21.3% in JN 14-95 and 30.3% in JN 72 under drought. Our findings suggest a need to move from uniform inoculation practices toward genotype-informed microbiome management. The two strategies provide a framework for leveraging host genetics in sustainable agriculture, highlighting that breeding and microbiome management should be integrated.
