Plant Physiology

López-Martín, María Jesús; Ferrándiz, Cristina; Gómez-Mena, Concepción

2025 Plant Physiology

doi: 10.1093/plphys/kiaf195pmid: 40342025

Flowering plants adjust their reproductive period to ensure reproductive success. This involves a tight control of both flower initiation and the termination of the flowering period to optimize resource allocation for seed production. The end of flowering is marked by the cessation of flower production by the inflorescence meristems, which enter a dormant-like state known as proliferative arrest. This process has been mainly studied in Arabidopsis (Arabidopsis thaliana) at the physiological, genetic, and molecular levels but remains to be characterized in other species, which could provide general mechanisms and the groundwork for designing biotechnological strategies aimed at controlling the duration of fruit/seed production. Solanum lycopersicum (tomato) is an excellent model for this goal because of its economic importance and the marked differences in plant architecture, meristem organization, and fruit development. By comparing plants producing fertile and parthenocarpic seedless fruits, we have determined that proliferative arrest in tomato is a reversible process triggered by seed formation. We have identified the seeds as the likely source of signals that instruct the meristems to arrest in a coordinated and quantitative manner. The presence of auxin and abscisic acid in exudates from fertile but not from parthenocarpic fruits and the effect of treating seedless fruits with exogenous auxin on proliferative arrest support a major role of these phytohormones in the communication between seeds and meristems. Our work supports the conservation of factors controlling proliferative arrest in flowering plants while providing insights into the regulation of this process.

Wang, Han-Qing; Zhao, Xing-Yu; Xiong, Ying-Ying; Cui, Lin-Mei; Xu, Xuejie; Mao, Chuanzao; Zhao, Fang-Jie

2025 Plant Physiology

doi: 10.1093/plphys/kiaf385pmid: 40880072

Plant roots are often severed during transplanting, but plants can recover from partial root loss through compensatory growth. However, the mechanisms regulating this compensatory growth are not fully understood. Here, we showed that cutting rice (Oryza sativa L.) seminal roots induces high auxin accumulation around the incision site. This auxin accumulation enhanced the expression of the transcription factor WUSCHEL-RELATED HOMEOBOX10 (OsWOX10) and promoted lateral root (LR) primordia development into long and thick L-type LRs, thus compensating for the partial loss of seminal roots. Removing the coleoptile or blocking shoot-to-root auxin transport inhibited auxin accumulation around the incision site and abolished compensatory LR growth. Three auxin efflux proteins, OsPIN1b, OsPIN1c, and OsPIN9, are expressed in the root vasculature and epidermis in the root tip meristem zone, and redundantly control shoot-to-root auxin transport and root tip auxin distribution. Knocking out all 3 PIN genes caused severe growth inhibition and loss of gravitropism, as well as diminished cutting-induced auxin accumulation and compensatory LR growth, whereas knockout of 1 or 2 genes had little effect. Soil transplanting experiments showed that weakened compensatory LR growth hinders plant growth and nutrient absorption after cutting. Jasmonic acid, reactive oxygen species, and cytosolic calcium signaling, which are important for wounding responses, were not involved in compensatory LR growth. Our study reveals that OsPIN1b, OsPIN1c, and OsPIN9 mediate shoot-to-root auxin transport, and that auxin accumulation around the incision site triggers compensatory LR growth after physical damage to rice roots.

Martin, Duncan G; Aspray, Elise K; Li, Shuai; Leakey, Andrew D B; Ainsworth, Elizabeth A

2025 Plant Physiology

doi: 10.1093/plphys/kiaf350pmid: 40796365

The co-occurrence of elevated tropospheric ozone concentrations and drought in agricultural regions is anticipated to increase with climate change. Both stressors negatively impact leaf photosynthetic capacity and stomatal conductance, contributing to reductions in biomass and yield. The interaction of ozone and drought stress is complex and under-researched, particularly in field settings. Stomatal closure in response to soil drying may provide protection from high ozone influx to leaves. Conversely, elevated ozone may prevent drought-induced stomatal closure, leading to depletion of soil water resources and exacerbation of drought stress. Here, we used Free Air Concentration Enrichment of ozone (100 ppb) and rainfall exclusion canopies (intercepting ∼40% of seasonal rainfall) to test potential interaction effects of elevated ozone and drought stress on soybean (Glycine max) leaf-level physiology and yield. Elevated ozone consistently reduced soybean Rubisco carboxylation capacity (−17%) and maximum electron transport capacity (−9%) across 3 yrs of study. Elevated ozone did not alter the relationships between soil moisture, abscisic acid, and stomatal conductance. Thus, there was no evidence indicating that ozone exposure prevented stomata from responding during drought. Yield was significantly reduced in soybeans exposed to elevated ozone, resulting from fewer seeds per plot and reduced seed size. The reduced precipitation treatment only affected yields in the driest growing season. These findings suggest that the effects of elevated ozone and drought are additive, rather than interactive, and dose dependent. The persistence of ozone damage under soil moisture depletion is likely to be exacerbated by global climate change.

Liu, Bo; Song, Zhaoyun; Qi, Xiaoquan

2025 Plant Physiology

doi: 10.1093/plphys/kiaf297pmid: 40623215

Cytochrome P450 enzymes (CYPs), a class of heme monooxygenases, are widely distributed across bacteria, archaea, and viruses, as well as in higher plants and animals. They regulate the metabolism of various endogenous substances and exogenous compounds, accounting for approximately 1% of the protein-coding genes in plants. These enzymes play a crucial role in the biosynthesis of plant bioactive metabolites, growth regulation, and stress adaptation. Currently, over 300,000 CYPs are recorded in databases, yet only a small fraction (less than 0.2%) has undergone functional characterization. This review focuses exclusively on the latest research progress (2020–2025) regarding 2 key aspects: the involvement of CYPs in the biosynthesis of important bioactive compounds in plants and their significant physiological functions in plant growth, development, and stress adaptation. The aim is to enhance our understanding and provide examples for the functional exploration of CYPs in plants, thereby paving the way for innovative applications in the field of biotechnological breeding and synthetic biology.

Lingwan, Maneesh

2025 Plant Physiology

doi: 10.1093/plphys/kiaf237pmid: 40920986

Russo, David A; Schneidmadel, Felix R; Zedler, Julie A Z

2025 Plant Physiology

doi: 10.1093/plphys/kiaf334pmid: 40796368

Cyanobacteria have played a leading role in elucidating the fundamental mechanisms behind oxygenic photosynthesis, carbon fixation, the circadian clock, and phototaxis. Such molecular processes rely on proteins at their core. Thus, proteomics has become an indispensable tool in building our understanding of these processes. Amongst the proteomic approaches used, “shotgun proteomics”, where complex protein mixtures are enzymatically digested into peptides and analyzed by liquid chromatography–mass spectrometry, has become the go-to technique for whole-proteome analysis. In this study, we introduce shotgun workflows that excel in speed, throughput, and sensitivity, and allow an in-depth description of the cyanobacterial proteome. The main features of these workflows are the improvement of sample cleanup and digestion through single-pot solid phase-enhanced sample preparation (SP3), the adoption of a previously validated trifluoroacetic acid lysis strategy, and the application of library-free data-independent acquisition. Using the established model organism Synechococcus elongatus PCC 7942, we show that these workflows exhibit high quantitative reproducibility and enable the detection of 83% to 85% of all open reading frames, the greatest single-shot coverage achieved so far for a cyanobacterium. These workflows require only a couple of hours of hands-on time and should be applicable to most, if not all, cyanobacterial species. Together with the rapid advancements in mass spectrometry technologies, this work has the potential to accelerate cyanobacterial proteomics.

Xue, Yongbiao

2025 Plant Physiology

doi: 10.1093/plphys/kiaf360pmid: 40811654

The S-RNase-based self-incompatibility (SI) system is a key mechanism in angiosperms that safeguards against self-pollination, thereby promoting outcrossing and genetic diversity. Governed by a single multiallelic S-locus, this system is regulated by pistil-expressed S-RNases and pollen-expressed S-locus F-box (SLF) proteins. In cross-pollination, SLFs assemble into Skp1/Cullin1//F-box (SCF) ubiquitin ligase complexes. These complexes selectively recognize non-self S-RNases and targets them for proteasomal degradation, allowing pollen tube growth to proceed unimpeded and fertilize the host ovule. In self-pollination, S-RNases capable of escaping degradation by self SCF complex undergo phase separation, forming cytoplasmic condensates that disrupt the cytoskeleton and redox homeostasis, ultimately triggering programmed cell death. Considered the ancestral SI system, S-RNase-based incompatibility likely emerged through the evolutionary linkage of ancestral S-RNase and SLF genes into a proto-S-locus. Other SI systems in angiosperms are hypothesized to have evolved secondarily via the loss of ancestral components within this evolutionary framework. Future research priorities include elucidating the molecular basis of SLF-mediated recognition of diverse S-RNases, unraveling the complex genetic architecture of the S-locus, and identifying novel SI mechanisms in understudied angiosperm lineages. This review underscores SI's molecular sophistication and evolutionary plasticity, highlighting its fundamental role in plant reproduction and its relevance to agricultural breeding strategies.

Tong, Chaobo; Ding, Yiran; Cheng, Xin; Liu, Lijiang; Liu, Xinmin; Zhang, Yuanyuan; Xia, Yutian; Li, Maoteng; Liu, Shengyi

2025 Plant Physiology

doi: 10.1093/plphys/kiaf358pmid: 40796182

Plant oil production is crucial for meeting the global demand for vegetable oils providing essential fatty acids and energy and for various industry uses. Plant oil biosynthesis is a complex biological process. Understanding the process is essential for improving oil crop productivity and nutritional quality. To target genetic improvement strategies of oil content, this review attempts to provide a broad view of oil biosynthesis in terms of the oil biosynthesis chain and was thus arranged into four sections: the code/control center of oil production—genetic and genomic insight into seed oil content control; the manufacturing center of oil production—oil biosynthesis and its regulation; the upstream raw material supply chains of oil production—carbon source, energy, and reductants; and the progresses, challenges, and strategies—oil content improvement by conventional and biotechnological breeding in the past and future. Within these sections, we highlight major-effect quantitative trait loci of oil content and the WRINKLED1- and SEEDSTICK-centered regulatory networks of oil biosynthesis and then revisit/update the significance of both photosynthetic and maternal effect on oil content and the central metabolic pathways and related bypasses in oil accumulation. Strategies for further improvement of oil content are discussed toward constructing integrated frameworks for increasing oil productivity. Overall, with this review we aim to consolidate the recent progress regarding oil biosynthesis in crops and provide insights into future research and practical applications to crop oil production.

Villadangos, Sabina; Munné-Bosch, Sergi

2025 Plant Physiology

doi: 10.1093/plphys/kiaf338pmid: 40749090

Aerobic organisms are prone to oxidative stress when meeting their metabolic and developmental demands, particularly under stressful environments. Here, we aimed to elucidate survival strategies to withstand an extreme drought stress in a clonal plant species at various organizational levels, including parental and offset rosettes. We explored physiological and morphological mechanisms underlying stress tolerance and offset maintenance in the tolerant plant species houseleek (Sempervivum tectorum) under controlled conditions—where potted plants were exposed to complete water withdrawal for up to 7 mo—and natural habitat conditions. We found an unexpected quiescent-like strategy through the maintenance of low oxidative levels in the leaves under severe stress. Moreover, S. tectorum plants employed a morphological strategy driven by the spatiotemporal senescence pattern along the rosette, thus protecting the apical inner bud under stress. Even with very low resource availability, the parent plant and the associated offspring adjusted their physiology, keeping the stolon-connected offsets alive for as long as required until rooting into the soil (sometimes for several months), without compromising the parental rosette. The quiescent response in the parental rosette is maintained despite an increasing number of unrooted offsets due to photoprotective and morphological adjustments in leaves, with higher endogenous ABA levels. These results revealed the mechanisms through which this species extended its survival during prolonged periods of drought stress without irreversible physiological costs of clonal reproduction for the whole genet.

Jené, Laia; Munné-Bosch, Sergi

2025 Plant Physiology

doi: 10.1093/plphys/kiaf185pmid: 40329863

The evolution of parasitic plants has been marked by a progressive relaxation of selective pressures associated with maintaining photosynthesis, resulting in a wide diversity in photosynthetic capacity within this group. In this study, we explored this diversity by examining several hemi- and holoparasitic plants, focusing on photoprotection. Our findings revealed a strongly conserved evolutionary association between vitamin E, PSII activity, and chlorophyll content in parasitic plants, with α-tocopherol consistently being identified as the predominant vitamin E form. To validate the antioxidant and photoprotective role of α-tocopherol in a plant with reduced photosynthetic capacity, we investigated the interaction between the stem holoparasitic plant field dodder (Cuscuta campestris Yunck.), which retains partial PSII activity and low chlorophyll levels, and its host, lentil plant (Lens culinaris Medik). This protective role, essential for controlling lipid peroxidation within chloroplasts, was demonstrated both in planta and in isolated chloroplasts from field dodder exposed to photoinhibitory conditions induced by the synthetic photosensitizer Rose Bengal and light. Notably, our findings highlight the final evolutionary step in the conserved role of vitamin E in photosynthesis and photoprotection as revealed through parasitic plants.