In recent years, there has been increased interest in the study of the molecular processes that affect semen traits. In this study, our aim was to identify quantitative trait loci (QTL) regions ...associated with four semen traits (motility, progressive motility, number of sperm cells per ejaculate and total morphological defects) in two commercial pig lines (L1: Large White type and L2: Landrace type). Since the number of animals with both phenotypes and genotypes was relatively small in our dataset, we conducted a weighted single-step genome-wide association study, which also allows unequal variances for single nucleotide polymorphisms. In addition, our aim was also to identify candidate genes within QTL regions that explained the highest proportions of genetic variance. Subsequently, we performed gene network analyses to investigate the biological processes shared by genes that were identified for the same semen traits across lines.
We identified QTL regions that explained up to 10.8% of the genetic variance of the semen traits on 12 chromosomes in L1 and 11 chromosomes in L2. Sixteen QTL regions in L1 and six QTL regions in L2 were associated with two or more traits within the population. Candidate genes SCN8A, PTGS2, PLA2G4A, DNAI2, IQCG and LOC102167830 were identified in L1 and NME5, AZIN2, SPATA7, METTL3 and HPGDS in L2. No regions overlapped between these two lines. However, the gene network analysis for progressive motility revealed two genes in L1 (PLA2G4A and PTGS2) and one gene in L2 (HPGDS) that were involved in two biological processes i.e. eicosanoid biosynthesis and arachidonic acid metabolism. PTGS2 and HPGDS were also involved in the cyclooxygenase pathway.
We identified several QTL regions associated with semen traits in two pig lines, which confirms the assumption of a complex genetic determinism for these traits. A large part of the genetic variance of the semen traits under study was explained by different genes in the two evaluated lines. Nevertheless, the gene network analysis revealed candidate genes that are involved in shared biological pathways that occur in mammalian testes, in both lines.
Embolism resistance of xylem tissue varies among species and is an important trait related to drought resistance, with anatomical attributes like pit membrane thickness playing an important role in ...avoiding embolism spread. Grafted Citrus trees are commonly grown in orchards, with the rootstock being able to affect the drought resistance of the whole plant. Here, we evaluated how rootstocks affect the vulnerability to embolism resistance of the scion using several rootstock/scion combinations. Scions of ‘Tahiti’ acid lime, ‘Hamlin’, ‘Pera’ and ‘Valencia’ oranges grafted on a ‘Rangpur’ lime rootstock exhibit similar vulnerability to embolism. In field‐grown trees, measurements of leaf water potential did not suggest significant embolism formation during the dry season, while stomata of Citrus trees presented an isohydric response to declining water availability. When ‘Valencia’ orange scions were grafted on ‘Rangpur’ lime, ‘IAC 1710’ citrandarin, ‘Sunki Tropical’ mandarin or ‘Swingle’ citrumelo rootstocks, variation in intervessel pit membrane thickness of the scion was found. The ‘Rangpur’ lime rootstock, which is known for its drought resistance, induced thicker pit membranes in the scion, resulting in higher embolism resistance than the other rootstocks. Similarly, the rootstock ‘IAC 1710’ citrandarin generated increased embolism resistance of the scion, which is highly relevant for citriculture.
Summary statement
Different Citrus rootstocks influence scion vulnerability to embolism, with ‘Rangpur’ lime inducing less vulnerability and thicker pit membranes. Besides, in field‐grown trees, measurements of leaf water potential did not suggest significant embolism formation even during the dry season.
Abstract
Carbon allocation between source and sink organs determines plant growth and is influenced by environmental conditions. Under water deficit (WD), plant growth is inhibited before ...photosynthesis and shoot growth tends to be more sensitive than root growth. However, the modulation of the source–sink relationship by rootstocks remains unsolved in citrus trees under WD. Citrus plants grafted on Rangpur lime are drought tolerant, which may be related to a fine coordination of the source–sink relationship for maintaining root growth. Here, we followed 13C allocation and evaluated physiological responses and growth of Valencia orange trees grafted on three citrus rootstocks (Rangpur lime, Swingle citrumelo and Sunki mandarin) under WD. As compared with plants on Swingle and Sunki rootstocks, ones grafted on Rangpur lime showed higher stomatal sensitivity to the initial variation of water availability and less accumulation of non-structural carbohydrates in roots under WD. High 13C allocation found in Rangpur lime roots indicates this rootstock has high sink demand associated with high root growth under WD. Our data suggest that Rangpur lime rootstock used photoassimilates as sources of energy and carbon skeletons for growing under drought, which is likely related to increases in root respiration. Taken together, our data revealed that carbon supply by leaves and delivery to roots are critical for maintaining root growth and improving drought tolerance, with citrus rootstocks showing differential sink strength under WD.
Feed efficiency is one of the most important parameters that affect beef production costs. The energy metabolism of skeletal muscle greatly contributes to variations in feed efficiency. However, ...information regarding differences in proteins involved in the energy metabolism of the skeletal muscle in beef cattle divergently identified for feed efficiency is scarce. In this study, we aimed to investigate energy metabolism of skeletal muscle of Nellore beef cattle, identified for low and high residual feed intake using a proteomics approach. We further assessed the expression of candidate microRNAs as a one of the possible mechanisms controlling the biosynthesis of the proteins involved in energy metabolism that were differentially abundant between high and low residual feed intake animals.
A greater abundance of 14-3-3 protein epsilon (P = 0.01) was observed in skeletal muscle of residual feed intake (RFI) high animals (RFI-High). Conversely, a greater abundance of Heat Shock Protein Beta 1 (P < 0.01) was observed in the skeletal muscle of RFI-Low cattle. A greater mRNA expression of YWHAE, which encodes the 14-3-3 protein epsilon, was also observed in the skeletal muscle of RFI-High animals (P = 0.01). A lower mRNA expression of HSPB1, which encodes the Heat Shock Protein Beta 1, was observed in the skeletal muscle of RFI-High animals (P = 0.01). The miR-665 was identified as a potential regulator of the 14-3-3 protein epsilon, and its expression was greater in RFI-Low animals (P < .001). A greater expression of miR-34a (P = 0.01) and miR-2899 (P < .001) was observed in the skeletal muscle of RFI-High animals, as both miRNAs were identified as potential regulators of HSPB1 expression.
Our results show that Nellore cattle divergently identified for feed efficiency by RFI present changes in the abundance of proteins involved in energy expenditure in skeletal muscle. Moreover, our data point towards that miR-665, miR34a and miR-2899 are likely involved in controlling both 14-3-3 epsilon and HSPB1 proteins identified as differentially abundant in the skeletal muscle of RFI-High and RFI-Low Nellore cattle.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Studies have shown that intramuscular adipogenesis and fibrogenesis may concomitantly occur in skeletal muscle of beef cattle. Thus, we hypothesized that the discrepancy of intramuscular fat content ...in beef from Nellore and Angus was associated with differences in intramuscular adipogenesis and fibrogenesis during the finishing phase. To test our hypothesis, longissimus muscle samples of Nellore (n = 6; BW = 372.5 ± 37.3 kg) and Angus (n = 6; BW = 382.8 ± 23.9 kg) cattle were collected for analysis of gene and protein expression, and quantification of intramuscular fat and collagen. Least-squares means were estimated for the effect of Breed and differences were considered at P ≤ 0.05. A greater intramuscular fat content was observed in skeletal muscle of Angus compared to Nellore cattle (P≤0.05). No differences were observed for mRNA expression of lipogenic and lipolytic markers ACC, FAS, FABP4, SERBP-1, CPT-2, LPL, and ACOX (P > 0.05) in skeletal muscle of Nellore and Angus cattle. Similarly, no differences were observed in mRNA expression of adipogenic markers Zfp423, PPARγ, and C/EBPα (P>0.05) However, a greater PPARγ protein content was observed in skeletal muscle of Angus compared to Nellore cattle (P≤0.05). A greater abundance of adipo/fibrogenic cells, evaluated by the PDGFRα content, was observed in skeletal muscle of Angus than Nellore cattle (P≤0.05). No differences in fibrogenesis were observed in skeletal muscle of Angus and Nellore cattle, which is in accordance with the lack of differences in intramuscular collagen content in beef from both breeds (P>0.05). These findings demonstrate that difference in intramuscular fat content is associated with a slightly enhanced adipogenesis in skeletal muscle of Angus compared to Nellore cattle, while no difference in fibrogenesis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract The effect of environmental gradients on the remarkable diversity of mountain‐associated plants and on the species' abilities to cope with climate change transcends species‐specific ...strategies. For instance, our understanding of the impact of thermal gradients on ecological divergences in populations of widely distributed species is limited, although it could provide important insights regarding species' response to climate change. Here, we investigated whether populations of an endemic species broadly distributed across an elevation gradient employ unique or multiple divergent ecological strategies according to specific environmental conditions. We hypothesised that populations employ distinct strategies, producing a tolerance‐avoidance trade‐off related to the thermal conditions they experience across elevations. We conducted our research with 125 individuals of Pitcairnia flammea (Bromeliaceae) sampled from various elevations spanning from sea level to ~2200 m and cultivated under the same conditions. To assess specific ecological strategies of P. flammea populations across elevations, we examined leaf temperature, heat and cold tolerances, as well as other structural/morphological, optical, physiological and biochemical leaf traits. We majorly observed that water‐saving traits diminish as elevation increases while membrane fluidity, majorly associated with unsaturated and very‐long‐chain lipids, enhances. Low‐elevation individuals of P. flammea invest in water storage tissues, which likely prevent excessive water loss through the intense transpiration rates under warming periods. Conversely, high‐elevation plants exhibit increased membrane fluidity, a possible response to the stiffening induced by low temperature. Our results revealed a tolerance‐avoidance trade‐off related to thermal strategies of populations distributed across an elevation gradient. Low‐elevation plants avoid excessive leaf temperature by investing in water‐saving traits to maintain transpiration rates. High‐elevation individuals, in turn, tend to invest in membrane properties to tolerate thermal variations, particularly cold events. Our findings challenge the conventional notion that plants' vulnerability to warming depends on species‐specific thermal tolerance by showing diverse thermal strategies on populations across an elevation gradient. Read the free Plain Language Summary for this article on the Journal blog.
Resumo O efeito dos gradientes ambientais na grande diversidade de plantas associadas a montanhas transcende as estratégias específicas de cada espécie. Nosso entendimento sobre o impacto dos gradientes térmicos nas divergências ecológicas em populações de espécies amplamente distribuídas, por exemplo, é limitado, embora possa fornecer informações importantes sobre a resposta das espécies às mudanças climáticas. Aqui, investigamos se populações de uma espécie endêmica e amplamente distribuída em um gradiente altitudinal, empregam estratégias ecológicas únicas ou múltiplas de acordo com condições ambientais específicas. Nossa hipótese é que as populações empregam estratégias que resultam em um equilíbrio entre tolerância e evitação relacionado às condições térmicas que experimentam em diferentes altitudes. Analisamos 125 indivíduos de Pitcairnia flammea (Bromeliaceae) amostrados em diversas altitudes, desde o nível do mar até cerca de 2.200 metros, e cultivados nas mesmas condições. Para avaliar as estratégias ecológicas específicas das populações de P. flammea , examinamos temperatura foliar, tolerâncias ao calor e ao frio, além de outros traços foliares estruturais/morfológicos, óticos, fisiológicos e bioquímicos. Vimos que características de economia de água diminuem à medida que a altitude aumenta, enquanto a fluidez da membrana, associada principalmente a lipídios insaturados e de cadeia muito longa, aumenta. Indivíduos de baixa altitude investem em tecidos de armazenamento de água, provavelmente prevenindo a perda excessiva de água durante períodos de aquecimento e com taxas intensas de transpiração. Por outro lado, plantas de altas altitudes possuem maior fluidez de membrana, uma possível resposta ao enrijecimento induzido por baixas temperaturas. Nossos resultados revelaram um equilíbrio entre tolerância e evitação relacionado às estratégias térmicas de populações distribuídas ao longo de um gradiente de altitude. Plantas de baixa altitude evitam temperaturas foliares excessivas investindo em características de economia de água para manter as taxas de transpiração. Indivíduos de alta altitude, por sua vez, tendem a investir em membranas que toleram variações térmicas, especialmente eventos frios. Nossas descobertas desafiam a noção convencional de que a vulnerabilidade das plantas ao aquecimento depende da tolerância térmica específica da espécie, mostrando estratégias térmicas diversas em populações ao longo de um gradiente de altitude.
Morpho-physiological strategies to deal with water deficit vary among citrus species and the chemical signaling through ABA and anatomical, hydraulic, and physiological traits were evaluated in ...saplings of Rangpur lime, Swingle citrumelo and Valencia sweet orange. Trunk and roots of Swingle citrumelo presented lower vessel diameter and higher vessel frequency as compared to the other species. However, relative water content at the turgor loss point (RWCTLP), the osmotic potential at full turgor (Ψ0), the osmotic potential at the turgor loss point (ΨTLP), bulk modulus of elasticity (ε) and the xylem water potential when hydraulic conductivity is reduced by 50% (Ψ50) and 88% (Ψ88) indicated similar hydraulic traits among citrus species, with Rangpur lime showing the highest hydraulic safety margin. Roots of Rangpur lime and Swingle citrumelo were more water conductive than ones of Valencia sweet orange, which was linked to higher stomatal conductance. Chemical signaling through ABA prevented shoot dehydration in Rangpur lime under water deficit, with this species showing a more conservative stomatal behavior, sensing, and responding rapidly to low soil moisture. Taken together, our results suggest that Rangpur lime – the drought tolerant species – has an improved control of leaf water status due to chemical signaling and effective stomatal regulation for reducing water loss as well as decreased root hydraulic conductivity for saving water resources under limiting conditions.
•Morpho-physiological strategies to deal with water deficit were studied in three citrus species.•Roots of Rangpur lime and Swingle citrumelo were more water conductive than ones of Valencia sweet orange.•Rangpur lime produced more ABA under water stress.•Rangpur lime has a conservative stomatal behavior, responding rapidly to drought.•ABA signaling, stomatal regulation of transpiration and low root hydraulic conductivity are linked to drought tolerance.
Reproductive traits such as number of stillborn piglets (SB) and number of teats (NT) have been evaluated in many genome-wide association studies (GWAS). Most of these GWAS were performed under the ...assumption that these traits were normally distributed. However, both SB and NT are discrete (e.g. count) variables. Therefore, it is necessary to test for better fit of other appropriate statistical models based on discrete distributions. In addition, although many GWAS have been performed, the biological meaning of the identified candidate genes, as well as their functional relationships still need to be better understood. Here, we performed and tested a Bayesian treatment of a GWAS model assuming a Poisson distribution for SB and NT in a commercial pig line. To explore the biological role of the genes that underlie SB and NT and identify the most likely candidate genes, we used the most significant single nucleotide polymorphisms (SNPs), to collect related genes and generated gene-transcription factor (TF) networks.
Comparisons of the Poisson and Gaussian distributions showed that the Poisson model was appropriate for SB, while the Gaussian was appropriate for NT. The fitted GWAS models indicated 18 and 65 significant SNPs with one and nine quantitative trait locus (QTL) regions within which 18 and 57 related genes were identified for SB and NT, respectively. Based on the related TF, we selected the most representative TF for each trait and constructed a gene-TF network of gene-gene interactions and identified new candidate genes.
Our comparative analyses showed that the Poisson model presented the best fit for SB. Thus, to increase the accuracy of GWAS, counting models should be considered for this kind of trait. We identified multiple candidate genes (e.g. PTP4A2, NPHP1, and CYP24A1 for SB and YLPM1, SYNDIG1L, TGFB3, and VRTN for NT) and TF (e.g. NF-κB and KLF4 for SB and SOX9 and ELF5 for NT), which were consistent with known newborn survival traits (e.g. congenital heart disease in fetuses and kidney diseases and diabetes in the mother) and mammary gland biology (e.g. mammary gland development and body length).
Drought tolerance is defined by several morpho-physiological mechanisms that together improve plant development under water-limiting conditions. Previously, we found root hydraulic redistribution is ...one of those mechanisms for water stress avoidance. Herein, we aimed to verify the physiological mechanisms associated with root hydraulic redistribution and its consequences for leaf gas exchange and plant growth. Valencia sweet orange scions were grafted onto either Rangpur lime or Swingle citrumelo rootstock. Each plant had two root systems of the same rootstock in distinct pots, which allowed partial irrigation. Our results revealed that citrus species redistribute water under drought and this varies when comparing rootstocks, with Rangpur lime showing higher ability to redistribute water than Swingle citrumelo. For the first time, root hydraulic redistribution in Rangpur lime was associated with osmotic adjustment in well-watered roots of plants facing water deficit. Rangpur lime also presented an effective stomatal regulation of water loss and decreases in leaf transpiration likely allowed water transport to roots under water deficit. As conclusion, we found that root hydraulic redistribution, osmotic adjustment and stomatal control of leaf gas exchange are important physiological mechanisms associated with drought tolerance induced by Rangpur lime rootstock.
Premise
Salt tolerance has rarely been investigated regionally in the neotropics and even more rarely in Orchidaceae, one of the largest families. Therefore, investigating local adaptation to salt ...spray and its physiological basis in Epidendrum fulgens, a neotropical orchid species, brings important new insights.
Methods
We assessed the degree of salt tolerance in E. fulgens by testing whether coastal populations are more tolerant to salt, which could point to local adaptation. To understand the physiological basis of such salt tolerance, we exposed wild‐collected individuals to salt spray for 60 days, then measured leaf expansion, osmotic potential, sodium leaf concentration, chlorophyll leaf index, chlorophyll fluorescence, relative growth rate, and pressure–volume curves.
Results
There is no local adaptation to salt spray since both inland and coastal plants have a high tolerance to salt stress. This tolerance is explained by the ability to tolerate high concentrations of salt in leaf tissues, which is related to the high succulence displayed by this species.
Conclusions
We showed an unprecedented salt tolerance level for an orchid species, highlighting our limited knowledge of that trait beyond the traditional studied groups. Another interesting finding is that salt tolerance in E. fulgens is linked to succulence, is widespread, and is not the result of local adaptation. We suggest that E. fulgens and its allied species could be an interesting group to explore the evolution of important traits related to tolerance to salt stress, like succulence.
PDF
