New Phytologist最新文献

• Plant survival in a warmer world requires the timely adjustment of biological processes to cyclical changes in the new environment. Circadian oscillators have been proposed to contribute to thermal adaptation and plasticity. However, the influence of temperature on circadian clock performance and its impact on plant behaviour in natural ecosystems are not well-understood.
• We combined bioinformatics, molecular biology and ecophysiology to investigate the effects of increasing temperatures on the functioning of the circadian clock in two closely related tree species from Patagonian forests that constitute examples of adaptation to different thermal environments based on their altitudinal profiles.
• Nothofagus pumilio, the species from colder environments, showed a major rearrangement of its transcriptome and reduced ability to maintain rhythmicity at high temperatures compared with Nothofagus obliqua, which inhabits warmer zones. In altitude-swap experiments, N. pumilio, but not N. obliqua, showed limited oscillator function in warmer zones of the forest, and reduced survival and growth.
• Our findings show that interspecific differences in the influence of temperature on circadian clock performance are associated with preferred thermal niches, and to thermal plasticity of seedlings in natural environments, highlighting the potential role of a resonating oscillator in ecological adaptation to a warming environment.

• Stress often induces plant trait plasticity, and microbial communities also alter plant traits. Therefore, it is unclear how much plasticity results from direct plant responses to stress vs indirect responses due to stress-induced changes in soil microbial communities.
• To test how microbes and microbial community responses to stress affect the ecology and potentially the evolution of plant plasticity, I grew plants in four stress environments (salt, herbicide, herbivory, and no stress) with microbes that had responded to these same environments or with sterile inoculant.
• Plants delayed flowering under stress only when inoculated with live microbial communities, and this plasticity was maladaptive. However, microbial communities responded to stress in ways that accelerated flowering across all environments. Microbes also affected the expression of genetic variation for plant flowering time and specific leaf area, as well as genetic variation for plasticity of both traits, and disrupted a positive genetic correlation for plasticity in response to herbicide and herbivory stress, suggesting that microbes may affect the pace of plant evolution.
• Together, these results highlight an important role for soil microbes in plant plastic responses to stress and suggest that microbes may alter the evolution of plant plasticity.

• Furanocoumarins (FCs) are plant defence compounds derived from the phenylpropanoid pathway via the coumarin umbelliferone that harbour some therapeutic benefits yet are the underlying cause of ‘grapefruit–drug interactions’ in humans. Most of the pathway genes have not been identified in citrus.
• We employed a genetic/Omics approach on citrus ancestral species and F1 populations of mandarin × grapefruit and mandarin × pummelo. Enzyme specificity was characterized by In vivo 2-oxoglutarate-dependent dioxygenase family (2OGD) activity assays.
• We identified a 2OGD multi-gene cluster involved in coumarin/FC/pyranocoumarin biosynthesis; Species lacking FCs in leaves/fruit were homozygous for a 655-base solo-LTR frame-disrupting insertion within one dual specificity C2′H/F6′H encoding 2OGD gene, demonstrating that integrity of this gene is fully correlated with the capacity to biosynthesize metabolites of the extended FC pathway in leaves/fruit. A second 2OGD is the prominent gene expressed in citrus roots, which contain a unique pattern of extended FC pathway metabolites, including the predominant pyranocoumarins. A third 2OGD gene encodes a single activity F6′H, which appears to be induced at the transcript level by citrus pathogens.
• The results provide insights into the genetic basis underlying the difference between citrus fruit FC producers (grapefruit and pummelo) and nonproducers (mandarin and orange) and provide a gene target to breed for FC-free varieties by marker-assisted breeding or genome editing.

Introduction and context

The role of cell wall composition in photosynthesis has only recently been proposed. Apparently contradictory results have been reported, but previous studies were often limited to single or closely related species. The aim of the present letter is to combine published and novel data on cell wall composition and photosynthesis limitations, including data for all the major land plant's phylogenetic groups (Supporting Information Methods S1; Dataset S1), to provide novel evidence on the importance of cell wall composition in determining mesophyll conductance to CO₂ diffusion (g_m) across land plants' phylogeny. We address the hypothesis that the pectin fraction of total major cell wall compounds is positively related to g_m and, consequently, to photosynthesis, when pooling species from across the entire phylogeny.

Introduction

The common method of delivering CRISPR/Cas reagents for genome editing in plants involves Agrobacterium-mediated transformation or preassembled CRISPR/Cas9 ribonucleoprotein complex delivery (Woo et al., 2015; Toda et al., 2019; Ye et al., 2020). These methods require labor-intensive and time-consuming plant tissue culture processes (Huang et al., 2022). Unfortunately, most plants exhibit extremely low efficiency in callus induction and regeneration; these technical challenges greatly hinder the application of genome editing. Recent developments in plant RNA virus-based expression vectors (Ma et al., 2020; Chen et al., 2022) provide a convenient, efficient, and cost-effective way for DNA-free genome editing in plants, leveraging the fact that virus RNA does not integrate into the genome. However, the stability of virus vectors is negatively correlated with the size of the inserted foreign genes. Consequently, achieving efficient expression of Streptococcus pyogenes Cas9 (SpCas9, c. 4.2 kb) by virus-based vectors remains challenging. Most reported viruses capable of delivering Cas9 proteins are negative-strand RNA viruses (Ma et al., 2020; Liu et al., 2023; Zhao et al., 2024), with only a few positive-strand RNA viruses identified (Uranga et al., 2021; Lee et al., 2024). Thus, delivering virus-based sgRNA vectors to plants overexpressing Cas9 is the most commonly used strategy (Ali et al., 2015; Jiang et al., 2019; Li et al., 2021). However, it is difficult to use this method to generate a Cas9-free mutant by crossing with wild-type (WT) plants with long flowering cycles, such as bamboo (Ye et al., 2017). Bamboo mosaic virus (BaMV) has a typical flexible filamentous virion structure with the positive-sense single-stranded RNA genome (Hsu et al., 2018). The BaMV-mediated expression system can effectively drive the expression of large foreign gene fragments (Jin et al., 2023). For the first time, we developed a BAMV-mediated Cas protein and sgRNA delivery system in WT Nicotiana benthamiana and bamboo. This approach enables targeted gene editing in noninfected leaves or stems in bamboo without the need for Cas9-expressing transgenic lines, leveraging BaMV's large cargo ability to transport Cas9 proteins.