-
The New Phytologist Jun 2024Pollination presents a risky journey for pollen grains. Pollen loss is sometimes thought to favour greater pollen investment to compensate for the inefficiency of...
Pollination presents a risky journey for pollen grains. Pollen loss is sometimes thought to favour greater pollen investment to compensate for the inefficiency of transport. Sex allocation theory, to the contrary, has consistently concluded that postdispersal loss should have no selective effect on investment in either sex function. But the intuitively appealing compensation idea continues to be raised despite the lack of theoretical endorsement. We address the theoretical issue with a model that directly represents pollen loss (and ovule loss through floral demise or loss of receptivity) as rate-dependent dynamical processes. These loss rates can be varied to examine the effect of pollination efficiency on optimal sex allocation. Pollen-ovule ratios follow from the sex allocation based on the resource costs of pollen and ovule production. This model confirms conventional findings that pollen loss should have essentially no effect on sexual resource allocation in large, panmictic populations. Pollen limitation of seed set does not alter this conclusion. These results force us to rethink the empirical association of pollination efficiency with low pollen-ovule ratios. This pattern could arise if efficient pollen transport commonly results in stigmatic deposition of cohorts of related pollen. Empirical evidence of correlated paternity supports this explanation.
PubMed: 38937955
DOI: 10.1111/nph.19929 -
The New Phytologist Jun 2024
PubMed: 38937950
DOI: 10.1111/nph.19905 -
The New Phytologist Jun 2024Recent droughts have strongly impacted forest ecosystems and are projected to increase in frequency, intensity, and duration in the future together with continued...
Recent droughts have strongly impacted forest ecosystems and are projected to increase in frequency, intensity, and duration in the future together with continued warming. While evidence suggests that tree diversity can regulate drought impacts in natural forests, few studies examine whether mixed tree plantations are more resistant to the impacts of severe droughts. Using natural variations in leaf carbon (C) and nitrogen (N) isotopic ratios, that is δC and δN, as proxies for drought response, we analyzed the effects of tree species richness on the functional responses of tree plantations to the pan-European 2018 summer drought in seven European tree diversity experiments. We found that leaf δC decreased with increasing tree species richness, indicating less drought stress. This effect was not related to drought intensity, nor desiccation tolerance of the tree species. Leaf δN increased with drought intensity, indicating a shift toward more open N cycling as water availability diminishes. Additionally, drought intensity was observed to alter the influence of tree species richness on leaf δN from weakly negative under low drought intensity to weakly positive under high drought intensity. Overall, our findings suggest that dual leaf isotope analysis helps understand the interaction between drought, nutrients, and species richness.
PubMed: 38934095
DOI: 10.1111/nph.19931 -
The New Phytologist Jun 2024Posttranslational modification of multiple ABA signaling components is an essential process for the adaptation and survival of plants under stress conditions. In our...
Posttranslational modification of multiple ABA signaling components is an essential process for the adaptation and survival of plants under stress conditions. In our previous study, we established that the pepper group A PP2C protein CaAITP1, one of the core components of ABA signaling, undergoes ubiquitination mediated by the RING-type E3 ligase CaAIRE1. In this study, we discovered an additional form of regulation mediated via the SUMOylation of CaAITP1. Pepper plants subjected to drought stress were characterized by reductions in both the stability and SUMOylation of CaAITP1 protein. Moreover, we identified a SUMO protease, Capsicum annuum DeSUMOylating Isopeptidase 2 (CaDeSI2), as a new interacting partner of CaAITP1. In vitro and in vivo analyses revealed that CaAITP1 is deSUMOylated by CaDeSI2. Silencing of CaDeSI2 in pepper plants led to drought-hypersensitive and ABA-hyposensitive phenotypes, whereas overexpression of CaDeSI2 in transgenic Arabidopsis plants resulted in the opposite phenotypes. Importantly, we found that the CaAITP1 protein was stabilized in response to the silencing of CaDeSI2, and CaDeSI2 and CaAITP1 co-silenced pepper plants were characterized by drought-tolerant phenotypes similar to those observed in CaAITP1-silenced pepper. Collectively, our findings indicate that CaDeSI2 reduces the stability of CaAITP1 via deSUMOylation, thereby positively regulating drought tolerance.
PubMed: 38934066
DOI: 10.1111/nph.19920 -
The New Phytologist Jun 2024Climate warming poses a significant threat to global crop production and food security. However, our understanding of the molecular mechanisms governing thermoresponsive...
Climate warming poses a significant threat to global crop production and food security. However, our understanding of the molecular mechanisms governing thermoresponsive development in crops remains limited. Here we report that the auxiliary subunit of N-terminal acetyltransferase A (NatA) in rice OsNAA15 is a prerequisite for rice thermoresponsive growth. OsNAA15 produces two isoforms OsNAA15.1 and OsNAA15.2, via temperature-dependent alternative splicing. Among the two, OsNAA15.1 is more likely to form a stable and functional NatA complex with the potential catalytic subunit OsNAA10, leading to a thermoresponsive N-terminal acetylome. Intriguingly, while OsNAA15.1 promotes plant growth under elevated temperatures, OsNAA15.2 exhibits an inhibitory effect. We identified two glycolate oxidases (GLO1/5) as major substrates from the thermoresponsive acetylome. These enzymes are involved in hydrogen peroxide (HO) biosynthesis via glycolate oxidation. N-terminally acetylated GLO1/5 undergo their degradation through the ubiquitin-proteasome system. This leads to reduced reactive oxygen species (ROS) production, thereby promoting plant growth, particularly under high ambient temperatures. Conclusively, our findings highlight the pivotal role of N-terminal acetylation in orchestrating the glycolate-mediated ROS homeostasis to facilitate thermoresponsive growth in rice.
PubMed: 38934055
DOI: 10.1111/nph.19928 -
Nutrients Jun 2024Patients with chronic kidney disease (CKD) suffer disproportionately from a high burden of cardiovascular disease, which, despite recent scientific advances, remains... (Review)
Review
Patients with chronic kidney disease (CKD) suffer disproportionately from a high burden of cardiovascular disease, which, despite recent scientific advances, remains partly understood. Vascular calcification (VC) is the result of an ongoing process of misplaced calcium in the inner and medial layers of the arteries, which has emerged as a critical contributor to cardiovascular events in CKD. Beyond its established role in blood clotting and bone health, vitamin K appears crucial in regulating VC via vitamin K-dependent proteins (VKDPs). Among these, the matrix Gla protein (MGP) serves as both a potent inhibitor of VC and a valuable biomarker (in its inactive form) for reflecting circulating vitamin K levels. CKD patients, especially in advanced stages, often present with vitamin K deficiency due to dietary restrictions, medications, and impaired intestinal absorption in the uremic environment. Epidemiological studies confirm a strong association between vitamin K levels, inactive MGP, and increased CVD risk across CKD stages. Based on the promising results of pre-clinical data, an increasing number of clinical trials have investigated the potential benefits of vitamin K supplementation to prevent, delay, or even reverse VC, but the results have remained inconsistent.
Topics: Humans; Vascular Calcification; Vitamin K; Renal Insufficiency, Chronic; Matrix Gla Protein; Vitamin K Deficiency; Extracellular Matrix Proteins; Calcium-Binding Proteins; Dietary Supplements; Cardiovascular Diseases; Biomarkers
PubMed: 38931153
DOI: 10.3390/nu16121798 -
The New Phytologist Jun 2024The homology of the single cotyledon of grasses and the ontogeny of the scutellum and coleoptile as the initial, highly modified structures of the grass embryo are...
The homology of the single cotyledon of grasses and the ontogeny of the scutellum and coleoptile as the initial, highly modified structures of the grass embryo are investigated using leaf developmental genetics and targeted transcript analyses in the model grass Zea mays subsp. mays. Transcripts of leaf developmental genes are identified in both the initiating scutellum and the coleoptile, while mutations disrupting mediolateral leaf development also disrupt scutellum and coleoptile morphology, suggesting that these grass-specific organs are modified leaves. Higher-order mutations in WUSCHEL-LIKE HOMEOBOX3 (WOX3) genes, involved in mediolateral patterning of plant lateral organs, inform a model for the fusion of coleoptilar margins during maize embryo development. Genetic, RNA-targeting, and morphological evidence supports models for cotyledon evolution where the scutellum and coleoptile, respectively, comprise the distal and proximal domains of the highly modified, single grass cotyledon.
PubMed: 38924134
DOI: 10.1111/nph.19922 -
The New Phytologist Jun 2024
PubMed: 38924094
DOI: 10.1111/nph.19930 -
The New Phytologist Jun 2024Rice tillering is one of the most important agronomical traits largely determining grain yield. Photosynthesis and nitrogen availability are two important factors...
Rice tillering is one of the most important agronomical traits largely determining grain yield. Photosynthesis and nitrogen availability are two important factors affecting rice tiller bud elongation; however, underlying mechanism and their cross-talk is poorly understood. Here, we used map-based cloning, transcriptome profiling, phenotypic analysis, and molecular genetics to understand the roles of the Decreased Tiller Number 1 (DTN1) gene that encodes the fructose-1,6-bisphosphate aldolase and involves in photosynthesis required for light-induced axillary bud elongation in rice. Deficiency of DTN1 results in the reduced photosynthetic rate and decreased contents of sucrose and other sugars in both leaves and axillary buds, and the reduced tiller number in dtn1 mutant could be partially rescued by exogenous sucrose treatment. Furthermore, we found that the expression of nitrogen-mediated tiller growth response 5 (NGR5) was remarkably decreased in shoot base of dtn1-2, which can be activated by sucrose treatment. Overexpression of NGR5 in the dtn1-2 could partially rescue the reduced tiller number, and the tiller number of dtn1-2 was insensitive to nitrogen supply. This work demonstrated that the sugar level regulated by photosynthesis and DTN1 could positively regulate NGR5 expression, which coordinates the cross-talk between carbon and nitrate to control tiller bud outgrowth in rice.
PubMed: 38923565
DOI: 10.1111/nph.19921 -
The New Phytologist Jun 2024
PubMed: 38923521
DOI: 10.1111/nph.19927