Eco‐physiology of maize crops under combined stresses Cagnola, Juan I.; D'Andrea, Karina E.; Rotili, Diego H. ...
The Plant journal : for cell and molecular biology,
March 2024, 2024-Mar, 2024-03-00, 20240301, Letnik:
117, Številka:
6
Journal Article
Recenzirano
SUMMARY
The yield of maize (Zea mays L.) crops depends on their ability to intercept sunlight throughout the growing cycle, transform this energy into biomass and allocate it to the kernels. Abiotic ...stresses affect these eco‐physiological determinants, reducing crop grain yield below the potential of each environment. Here we analyse the impact of combined abiotic stresses, such as water restriction and nitrogen deficiency or water restriction and elevated temperatures. Crop yield depends on the product of kernel yield per plant and the number of plants per unit soil area, but increasing plant population density imposes a crowding stress that reduces yield per plant, even within the range that maximises crop yield per unit soil area. Therefore, we also analyse the impact of abiotic stresses under different plant densities. We show that the magnitude of the detrimental effects of two combined stresses on field‐grown plants can be lower, similar or higher than the sum of the individual stresses. These patterns depend on the timing and intensity of each one of the combined stresses and on the effects of one of the stresses on the status of the resource whose limitation causes the other. The analysis of the eco‐physiological determinants of crop yield is useful to guide and prioritise the rapidly progressing studies aimed at understanding the molecular mechanisms underlying plant responses to combined stresses.
Significance Statements
Drought, nitrogen deficiency, warming temperatures and neighbour crowding reduce the grain yield of plants. Here we analyse how these stresses impact on maize crops in the field when combined.
The increasing importance of sustainability in energy production has led to a global commitment to the use of fuels derived from renewable biological sources, such as biodiesel produced from plant ...crops or biomass residues, that do not compete with human food for their production. For a biofuel to be considered biodiesel, it must satisfy the specifications described in the UNE 14214, with the UNE‐EN 14103 referring to the determination of fatty acid methyl ester content. This standard applies gas chromatography as an analytical technique. Gas chromatography is a widely used technique in the analysis of methyl ester although it has a number of drawbacks such as: long analysis times, a high consumption of high‐quality gases and internal standards, does not allow the analysis of different compounds with the same column, etc. From an industrial production point of view, is necessary to know the fatty acid methyl ester content in biodiesel samples quickly. This paper studies the development of an analytical method using Fourier transform infrared spectroscopy (FTIR) as alternative to gas chromatography (GC), since it is a simple, rapid, and precise analytical technique to quantify fatty acid methyl ester content in biofuel samples.
•Enhanced variation in plasticity after correction of the lowermost percentile.•Large plasticity for anthesis-silking interval, grain yield and kernel number.•Reduced plasticity for developmental ...traits and kernel weight.•Mean inbreds phenotypic plasticity had a larger variation than that of hybrids.•Lack of relationship between traits heritability and their phenotypic plasticity.
Correct characterization of heritability and phenotypic plasticity (PP) is critical for breeding purposes. The latter refers to the variation range of a trait in response to changes in the environment and has been assessed as the difference between percentiles 10th (P10) and 90th (P90) of each trait, which does not reflect below the median (P50) variations to the same extent as the above the median ones. This inconsistency may affect the classification of stable (low PP) or plastic (high PP) given to traits, as well as their relative ranking and PP relationship with heritability. The objectives of current research were to evaluate corrected PP (PPC) variation in grain yield (GY) and related secondary traits among contrasting maize genotypic groups (inbreds and hybrids) grown under contrasting water regimes (WR) and nitrogen (N) availabilities. The relationship between PPC and broad-sense heritability (H2) was also assessed. Field experiments were conducted during three (N) or seven (WR) growing seasons at two mid-latitude environments of Argentina. Measured traits were days and thermal time to 50% anthesis (A50 and TTA) and to 50% silking (S50 and TTS), the anthesis-silking interval in days (ASID) and in TT (ASITT), plant height (Ph), prolificacy (Pr), GY, kernel numbers (KN), and kernel weight (KW). Values for percentiles 10th (P10), 50th (P50) and 90th (P90) of each trait were identified for each treatment combination. P50 was set to 1, and values obtained for P10 and P90 were expressed as ratios with P50. P10 was corrected (P10C= P50 – P50/P10) to reflect the below P50 variations to the same extent as those above P50. Corrected PP was estimated as PPC= P90 - P10C. P90 values of all traits corresponded to non-stressed plots whereas P10C values corresponded to stressed plots, except for ASIs (opposite trend). A large plasticity (PPC>mean PPC) was usually verified for ASIs, GY and KN. Mean inbreds PPC had a larger variation than mean hybrids PPC (+19% for WR and +29% for N), except for GY under contrasting WR (hybrids > inbreds). A common trend across all evaluated traits was the markedly larger effect on PPC of P10C than of P90, in agreement with the predominant representation of stressful conditions by the former and in contrast to previous studies where no correction was performed on P10. Our results demonstrated the lack of relationship between H2 and PP and improved current knowledge about the importance of environment modulation on PP of most expansion-related and production traits, highlighting the relevance of the evaluated resource (water or N) as well as of the genotypic group (hybrids or inbreds) on final phenotype expression.
Maize (Zea mays L.) ear‐related traits conducive to final kernel number per plant (KNP) are currently considered key determinants of kernel set under abiotic stress. Understanding of the variation ...between parental inbred lines and their hybrids is limited. The objective of this work was to analyze the genotypic variation between a set of inbred lines and some of their derived hybrids for (a) total number of spikelets per ear, (b) silk extrusion dynamics, (c) KNP, and (d) sources of loss in KNP (i.e., silk and kernel abortions) under high and limited N supply. In inbreds, variations in KNP were strongly explained by variations in silk extrusion rate (SER) and silk abortion. In contrast, hybrid KNP was explained by the number of spikelet per ear, exposed silks on Day 5 (ESD5), and extruded silks (TES), as well as silk extrusion per unit area (ESMAX). Heterosis across N levels was high for KNP, ESMAX, SER, kernel abortion, and ESD5. Strong parent–progeny relationships (r ≥ .69, P < .01) were computed for reproductive morphology traits (TES, total spikelets) at both N levels, whereas (a) KNP, sources of loss, and ESMAX were highly heritable exclusively under high N supply, and (b) ESD5 was a good predictor of hybrids KNP only at low N supply. Based on its high heterosis across environments and good parent–progeny relationship for KNP under N deficiency, ESD5 quantification should be part of breeding programs aimed to low‐N environments, depending upon the development of image‐based plant and crop phenotyping.
Conceptual representation of the response of absolute heterosis plasticity to traits plasticities for both genotypic groups. Both plasticities are expressed as the response (i.e., slope) to the ...environment (i.e., environmental index). ASI: anthesis-silking interval, BIOPM: aboveground biomass at physiological maturity, EGRCP: apical ear growth rate during the critical period, KNP: kernel number per plant, KW: individual kernel weight, PGRCP: plant growth rate during the critical period, PGY: plant grain yield, Pr: prolificacy.
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•A balanced environmental index is a robust tool for phenotypic plasticity analysis.•The response to the environmental index was linear, bilinear or null depending on the trait.•A tight association exists between phenotypic and absolute heterosis plasticities.•The positive trend in mentioned association is driven by hybrids.•The relative benefit of exploiting heterosis for grain yield is not environment-dependent.
Maize grain yield is determined by genotype (G), environment (E) and G × E interaction effects that influence the expression of traits along the crop cycle. Inbreds and hybrids may differ in their responses to fluctuations in environmental conditions, determining changes in heterosis levels across environments and consequently the target environment for their evaluation. The objectives of this work were (i) to compare traits related to grain yield, aboveground biomass production and its partitioning in two contrasting genotypic groups (inbreds and hybrids) and (ii) to analyze their performance across environments for the assessment of their phenotypic plasticity as well as environmental effects on the expression of heterosis. We built a balanced environmental index based on normalized plant grain yield (BEINPGY) from 14 contrasting environments using a 6-inbred complete diallel mating design and analyzed the response of the 12 evaluated traits to this index for each genotypic group. This approach allowed us to (i) differentiate among traits with simple linear (grain yield, total biomass, kernel numbers, the anthesis-silking interval and plant reproductive efficiency), bilinear (harvest index, individual kernel weight, prolificacy and apical ear reproductive efficiency) or no response (ear and plant growth rates around flowering as well as their relationship) in phenotypic plasticity of each group to the BEINPGY, and (ii) group traits depending upon their absolute heterosis response (i.e., heterosis plasticity) to the BEINPGY, which varied in sign (positive, null or negative) depending upon the trait. There was a clear and positive relationship between absolute heterosis plasticity and traits plasticities, which was mainly driven by hybrids. Genotypic groups differed in the association patterns of traits values per se as well as of their phenotypic plasticities, indicative of the different genetic bases that determine them. The fact that percent heterosis for grain yield and other relevant secondary traits did not vary across environments, whereas heritability is expected to decrease under stressful conditions, may contribute to guide future breeding efforts aiming to develop superior hybrids with successful performance, particularly in future challenging environmental scenarios.
In obesity, depletion of KCs expressing CRIg (complement receptor of the Ig superfamily) leads to microbial DNA accumulation, which subsequently triggers tissue inflammation and insulin resistance. ...However, the mechanism underlying obesity-mediated changes in KC complement immune functions is largely unknown.
Using KC-specific deactivated Cas9 transgenic mice treated with guide RNA, we assessed the effects of restoring CRIg or the serine/arginine-rich splicing factor 3 (SRSF3) abundance on KC functions and metabolic phenotypes in obese mice. The impacts of weight loss on KC responses were evaluated in a diet switch mouse model. The role of SRSF3 in regulating KC functions was also evaluated using KC-specific SRSF3 knockout mice. Here, we report that overexpression of CRIg in KCs of obese mice protects against bacterial DNA accumulation in metabolic tissues. Mechanistically, SRSF3 regulates CRIg expression, which is essential for maintaining the CRIg+ KC population. During obesity, SRSF3 expression decreases, but it is restored with weight loss through a diet switch, normalizing CRIg+ KCs. KC SRSF3 is also repressed in obese human livers. Lack of SRSF3 in KCs in lean and obese mice decreases their CRIg+ population, impairing metabolic parameters. During the diet switch, the benefits of weight loss are compromised due to SRSF3 deficiency. Conversely, SRSF3 overexpression in obese mice preserves CRIg+ KCs and improves metabolic responses.
Restoring SRSF3 abundance in KCs offers a strategy against obesity-associated tissue inflammation and insulin resistance by preventing bacterial DNA accumulation.
Maize (Zea mays L.) kernel weight (KW) and grain yield depend on plant growth during active grain filling and reserves use. The objective of our study was to analyze the phenotypic and genotypic ...variation in these traits in a family of recombinant inbred lines (RIL). In two field experiments we measured plant grain yield (PGY) and its components (KW and kernel number per plant, KNP), biomass production per plant and per kernel during active grain filling, and apparent reserves use (ARU) per plant (ARUP, difference between PGY and plant biomass production during active grain filling) and per kernel (ARUK, difference between KW and plant biomass production per kernel during active grain filling). Heritability (h2) and phenotypic plasticity were computed for all traits. Large differences were always evident among genotypes, but phenotypic plasticity was (i) low for KW and plant biomass at R2 and physiological maturity; (ii) intermediate for KNP and PGY; and (iii) high for plant growth, plant growth per kernel after R2, and ARUs. Traits with highest h2 were KW (0.70), KNP (0.61), and ARUP (0.59). Final KW was related to plant growth per kernel (r2 = 0.64; P < 0.001) but not to ARUK, and ARUP was driven (r2 ≥ 0.49; P < 0.001) by KNP. Because of its positive relationship with KNP (main determinant of PGY), high h2 and high phenotypic plasticity, breeding must consider the increase in ARUP for improving grain yield, an objective that needs to be coupled with large reserves accumulation before silking to avoid the risk of lodging.
ABSTRACT
Genotype × environment interaction explains a proportion of variation for crop yield performance often higher than the genotypic effect, becoming a major impediment to genetic progress. In ...this study, a crop model of yield determination in combination with three‐mode principal component analysis (PCA) was used to analyze genotype × environment × attribute interaction. A full diallel of six maize (Zea mays L.) inbred lines was grown in 10 environments in Argentina. The first environment component associated with the common genotype and attribute pattern across environments revealed that the main numerical determinant of plant grain yield (PGY) was kernel weight and not kernel number per plant (KNP). The second environment component established the importance of genotype × year interaction for anthesis‐silking interval (ASI), KNP, and PGY when water deficit prevailed during the critical period of yield determination and revealed a lack of association between ASI and ear growth rate during this period. The three‐mode PCA described the specific patterns of hybrid performance across environments, revealing physiological processes that separate inbred lines that contribute to drought tolerance, but at the expense of limiting PGY under well‐watered conditions. The use of a crop growth model allowed interpretation of the effects of environment conditions on main physiological determinants of grain yield, exposing the effects of water supply/demand ratio as a possible driver of differential performance of inbred lines.
Large-scale simulations of two-dimensional bidisperse granular fluids allow us to determine spatial correlations of slow particles via the four-point structure factor S(4)(q,t). Both cases, elastic ...(ϵ=1) and inelastic (ϵ<1) collisions, are studied. As the fluid approaches structural arrest, i.e., for packing fractions in the range 0.6≤ϕ≤0.805, scaling is shown to hold: S(4)(q,t)/χ(4)(t)=s(qξ(t)). Both the dynamic susceptibility χ(4)(τ(α)) and the dynamic correlation length ξ(τ(α)) evaluated at the α relaxation time τ(α) can be fitted to a power law divergence at a critical packing fraction. The measured ξ(τ(α)) widely exceeds the largest one previously observed for three-dimensional (3d) hard sphere fluids. The number of particles in a slow cluster and the correlation length are related by a robust power law, χ(4)(τ(α))≈ξ(d-p)(τ(α)), with an exponent d-p≈1.6. This scaling is remarkably independent of ϵ, even though the strength of the dynamical heterogeneity at constant volume fraction depends strongly on ϵ.
Emerging evidence indicates the critical roles of microbiota in mediating host cardiac functions in ageing, however, the mechanisms underlying the communications between microbiota and cardiac cells ...during the ageing process have not been fully elucidated. Bacterial DNA was enriched in the cardiomyocytes of both ageing humans and mice. Antibiotic treatment remarkably reduced bacterial DNA abundance in ageing mice. Gut microbial DNA containing extracellular vesicles (mEVs) were readily leaked into the bloodstream and infiltrated into cardiomyocytes in ageing mice, causing cardiac microbial DNA enrichment. Vsig4
macrophages efficiently block the spread of gut mEVs whereas Vsig4
cell population was greatly decreased in ageing mice. Gut mEV treatment resulted in cardiac inflammation and a reduction in cardiac contractility in young Vsig4
mice. Microbial DNA depletion attenuated the pathogenic effects of gut mEVs. cGAS/STING signaling is critical for the effects of microbial DNA. Restoring Vsig4
macrophage population in ageing WT mice reduced cardiac microbial DNA abundance and inflammation and improved heart contractility.
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