Transcriptomic Analyses Reveal That and Have More Complex Responses under Combined Heat and Drought than under Individual Stressors.

Increasing exposure to unfavorable temperatures and water deficit imposes major constraints on most crops worldwide. Despite several studies regarding coffee responses to abiotic stresses, transcriptome modulation due to simultaneous stresses remains poorly understood. This study unravels transcriptomic responses under the combined action of drought and temperature in leaves from the two most traded species: cv.

Uncovering the wide protective responses in spp. leaves to single and superimposed exposure of warming and severe water deficit.

Climate changes boosted the frequency and severity of drought and heat events, with aggravated when these stresses occur simultaneously, turning crucial to unveil the plant response mechanisms to such harsh conditions. Therefore, plant responses/resilience to single and combined exposure to severe water deficit (SWD) and heat were assessed in two cultivars of the main coffee-producing species: cv. Icatu and cv.

Carbon gain is coordinated with enhanced stomatal conductance and hydraulic architecture in coffee plants acclimated to elevated [CO]: The interplay with irradiance supply.

We recently demonstrated that, under elevated [CO] (eC), coffee (Coffea arabica L.) plants grown at high light (HL), but not at low light (LL), display higher stomatal conductance (g) than at ambient [CO] (aC). We then hypothesized that the enhanced g at eC/HL, if sustained at the long-term, would lead to adjustments in hydraulic architecture.

Growth and Leaf Gas Exchange Upregulation by Elevated [CO] Is Light Dependent in Coffee Plants.

Coffee ( L.) plants have been assorted as highly suitable to growth at elevated [CO] (e), although such suitability is hypothesized to decrease under severe shade. We herein examined how the combination of e and contrasting irradiance affects growth and photosynthetic performance.

Protective Responses at the Biochemical and Molecular Level Differ between a L. Hybrid and Its Parental Genotypes to Supra-Optimal Temperatures and Elevated Air [CO].

Climate changes with global warming associated with rising atmospheric [CO] can strongly impact crop performance, including coffee, which is one of the most world's traded agricultural commodities. Therefore, it is of utmost importance to understand the mechanisms of heat tolerance and the potential role of elevated air CO (eCO) in the coffee plant response, particularly regarding the antioxidant and other protective mechanisms, which are crucial for coffee plant acclimation. For that, plants of cv.

The relative area of vessels in xylem correlates with stem embolism resistance within and between genera.

The resistance of xylem conduits to embolism is a major factor defining drought tolerance and can set the distributional limits of species across rainfall gradients. Recent work suggests that the proximity of vessels to neighbors increases the vulnerability of a conduit. We therefore investigated whether the relative vessel area of xylem correlates with intra- and inter-generic variation in xylem embolism resistance in species pairs or triplets from the genera Acer, Cinnamomum, Ilex, Quercus and Persea, adapted to environments differing in aridity.

Exploring leaf hydraulic traits to predict drought tolerance of Eucalyptus clones.

Ongoing changes in climate, and the consequent mortality of natural and cultivated forests across the globe, highlight the urgent need to understand the plant traits associated with greater tolerance to drought. Here, we aimed at assessing key foliar traits, with a focus on the hydraulic component, that could confer a differential ability to tolerate drought in three commercial hybrids of the most important Eucalyptus species utilized in tropical silviculture: E. urophyla, E.

Impaired auxin signaling increases vein and stomatal density but reduces hydraulic efficiency and ultimately net photosynthesis.

Auxins are known to regulate xylem development in plants, but their effects on water transport efficiency are poorly known. Here we used tomato plants with the diageotropica mutation (dgt), which has impaired function of a cyclophilin 1 cis-trans isomerase involved in auxin signaling, and the corresponding wild type (WT) to explore the mutation's effects on plant hydraulics and leaf gas exchange. The xylem of the dgt mutant showed a reduced hydraulically weighted vessel diameter (Dh) (24-43%) and conduit number (25-58%) in petioles and stems, resulting in lower theoretical hydraulic conductivities (Kt); on the other hand, no changes in root Dh and Kt were observed.

Xylem embolism spread is largely prevented by interconduit pit membranes until the majority of conduits are gas-filled.

Xylem embolism resistance varies across species influencing drought tolerance, yet little is known about the determinants of the embolism resistance of an individual conduit. Here we conducted an experiment using the optical vulnerability method to test whether individual conduits have a specific water potential threshold for embolism formation and whether pre-existing embolism in neighbouring conduits alters this threshold. Observations were made on a diverse sample of angiosperm and conifer species through a cycle of dehydration, rehydration and subsequent dehydration to death.

Limited plasticity in embolism resistance in response to light in leaves and stems in species with considerable vulnerability segmentation.

Xylem resistance to embolism is a key metric determining plant survival during drought. Yet, we have a limited understanding of the degree of plasticity in vulnerability to embolism. Here, we tested whether light availability influences embolism resistance in leaves and stems.

A Transcriptomic Approach to Understanding the Combined Impacts of Supra-Optimal Temperatures and CO Revealed Different Responses in the Polyploid and Its Diploid Progenitor .

Understanding the effect of extreme temperatures and elevated air (CO) is crucial for mitigating the impacts of the coffee industry. In this work, leaf transcriptomic changes were evaluated in the diploid and its polyploid , grown at 25 °C and at two supra-optimal temperatures (37 °C, 42 °C), under ambient (aCO) or elevated air CO (eCO). Both species expressed fewer genes as temperature rose, although a high number of differentially expressed genes (DEGs) were observed, especially at 42 °C.

Specific leaf area is modulated by nitrogen via changes in primary metabolism and parenchymal thickness in pepper.

Nitrogen promotes changes in SLA through metabolism and anatomical traits in Capsicum plants. Specific leaf area (SLA) is a key trait influencing light interception and light use efficiency that often impacts plant growth and production. SLA is a key trait explaining growth variations of plant species under different environments.

Elevated [CO] benefits coffee growth and photosynthetic performance regardless of light availability.

Despite being evolved in shaded environments, most coffee (Coffea arabica L.) is cultivated worldwide under sparse shade or at full sunlight. Coffee is ranked as greatly responsive to climate change (CC), and shading has been considered an important management strategy for mitigating the harmful CC outcomes on the crop.

Transcriptomic Leaf Profiling Reveals Differential Responses of the Two Most Traded Coffee Species to Elevated [CO].

As atmospheric [CO] continues to rise to unprecedented levels, understanding its impact on plants is imperative to improve crop performance and sustainability under future climate conditions. In this context, transcriptional changes promoted by elevated CO (eCO) were studied in genotypes from the two major traded coffee species: the allopolyploid (Icatu) and its diploid parent, (CL153). While Icatu expressed more genes than CL153, a higher number of differentially expressed genes were found in CL153 as a response to eCO.

Intrinsic non-stomatal resilience to drought of the photosynthetic apparatus in Coffea spp. is strengthened by elevated air [CO2].

Growing water restrictions associated with climate changes constitute daunting challenges to crop performance. This study unveils the impacts of moderate (MWD) or severe (SWD) water deficit, and their interaction with air [CO2], on the photosynthetic apparatus of Coffea canephora Pierre ex A. Froehner cv.

The interplay between irrigation and fruiting on branch growth and mortality, gas exchange and water relations of coffee trees.

The overall coordination between gas exchanges and plant hydraulics may be affected by soil water availability and source-to-sink relationships. Here we evaluated how branch growth and mortality, leaf gas exchange and metabolism are affected in coffee (Coffea arabica L.) trees by drought and fruiting.

Resilient and Sensitive Key Points of the Photosynthetic Machinery of spp. to the Single and Superimposed Exposure to Severe Drought and Heat Stresses.

This study unveils the single and combined drought and heat impacts on the photosynthetic performance of cv. Icatu and cv. Conilon Clone 153 (CL153).

How do wheat plants cope with Pyricularia oryzae infection? A physiological and metabolic approach.

The infection of wheat leaves by Pyricularia oryzae induced remarkable reprogramming of the primary metabolism (amino acids, sugars, and organic acids) in favor of a successful fungal infection and certain changes were conserved among cultivars regardless of their level of resistance to blast. Wheat blast, caused by Pyricularia oryzae, has become one of the major threats for food security worldwide. Here, we investigated the behavior of three wheat cultivars (BR-18, Embrapa-16, and BRS-Guamirim), differing in their level of resistance to blast, by analyzing changes in cellular damage, antioxidative metabolism, and defense compounds as well as their photosynthetic performance and metabolite profile.

Osmotic adjustment and hormonal regulation of stomatal responses to vapour pressure deficit in sunflower.

Dynamic variation of the stomatal pore in response to changes in leaf-air vapour pressure difference (VPD) constitutes a critical regulation of daytime gas exchange. The stomatal response to VPD has been associated with both foliage abscisic acid (ABA) and leaf water potential (Ψ  ); however, causation remains a matter of debate. Here, we seek to separate hydraulic and hormonal control of stomatal aperture by manipulating the osmotic potential of sunflower leaves.

What does the RuBisCO activity tell us about a C-CAM plant?

Plants that perform the Crassulacean acid metabolism (CAM), which obtain CO overnight and convert it mainly in malic acid, successfully grow in environments with water and nutrient shortages, that is partly associated with their higher water- and nitrogen-use efficiencies. Water and nutrient limitations can impair photosynthesis through the reduction of RuBisCO and increment of photorespiration, disturbing the plant carbon balance. In this context, we conducted a controlled experiment with the epiphytic C-CAM bromeliad Guzmania monostachia to investigate how the combined water and nutritional deficits affect the activity of RuBisCO and its activation state (RAS), and to evaluate the efficiency of photosynthesis during the transition from C to CAM.

Silicon nutrition mitigates the negative impacts of iron toxicity on rice photosynthesis and grain yield.

Excess iron (Fe) is commonly observed in wetland rice (Oryza sativa L.) plants, impairing crop growth and productivity. Some information suggests that silicon (Si) can reduce Fe content in leaves and roots of rice (vegetative phase), but nothing is known if Si could mitigate the effects of Fe toxicity on rice production and photosynthesis.