Ovule Abortion Research Articles

A Moderate Water Deficit Induces Profound Changes in the Proteome of Developing Maize Ovaries.

Water deficit is a major cause of yield loss for maize (Zea mays), leading to ovary abortion when applied at flowering time. To help understand the mechanisms involved in this phenomenon, the proteome response to water deficit has been analysed in developing ovaries at the silk emergence stage and five days later. Differential analysis, abundance pattern clustering and co-expression networks were performed in order to draw a general picture of the proteome changes all along ovary development and under the effect of water deficit. The results show that even mild water deficit has a major impact on ovary proteome, but this impact is very different from a response to stress. A part of the changes can be related to a slowdown of ovary development, while another part cannot. In particular, ovaries submitted to water deficit show an increase in proteins involved in protein biosynthesis and in vesicle transport together with a decrease in proteins involved in amino acid metabolism and proteolysis. According to the functions of increased proteins, the changes may be linked to auxin, brassinosteroids and jasmonate signalling but not abscisic acid.

The correlation between embryo rescue and hormonal changes in seedless grapes.

After normal pollination and fertilization of pseudoparthenocarpic seedless grapes, their embryos often stop developing due to certain developmental factors, resulting in embryo abortion. Hybrid breeding using seedless grapes as the maternal parent requires embryo rescue breeding technology. This technology plays a crucial role in seedless grape breeding. Although previous studies have extensively explored this technology, knowledge regarding its impact on embryo abortion and the effectiveness of rescue techniques remains limited. This study aimed to investigate the correlation between embryo rescue and hormonal changes in seedless grapes. Four Eurasian seedless grape cultivars, "Thompson Seedless," "Flame Seedless," "Heshi Seedless," and "Ruby Seedless," were selected for examination. We investigated endogenous hormone levels, including indole-3-acetic acid (IAA), gibberellic acid (GA3), and abscisic acid (ABA), in both berries and in vitro ovules during the most suitable embryo rescue time for these cultivars. Based on the observed fluctuations in endogenous hormone levels and previous research findings, appropriate doses of exogenous hormones, such as IAA, GA3, and ABA, were applied during seedless grape embryo rescue. The results indicated significant differences in endogenous hormone levels between berries with varying ovule counts of the same cultivar and ovules cultured in vitro, suggesting a hormonal influence on ovule abortion and embryo development in seedless grapes. Further research has identified effective ratios of exogenous hormones: 30 mg·L-1 IAA + 30 mg·L-1 ABA for berry ovule development, 1.0 mg·L-1 IAA + 2.0mg·L-1 6-benzylaminopurine (6-BA) + 1.0 mg·L-1 GA3 + 1.0 mg·L-1 ABA for in vitro ovule development, and 1.0 mg·L-1 IAA + 2.0 mg·L-1 6-BA + 1.0 mg·L-1 GA3 for embryo germination and seedling formation. In summary, hormonal changes significantly influence ovule and embryo development and are closely related to seedless grape embryo rescue breeding. This study deepened our understanding of the correlation between seedless grape embryo rescue and hormonal changes. It also resulted in the successful production of a batch of embryo rescue seedlings, further improving embryo rescue breeding technology and providing new germplasm materials for developing new seedless grape cultivars.

Genome-Wide Characterization and Functional Validation of the ACS Gene Family in the Chestnut Reveals Its Regulatory Role in Ovule Development.

Ovule abortion significantly contributes to a reduction in chestnut yield. Therefore, an examination of the mechanisms underlying ovule abortion is crucial for increasing chestnut yield. In our previous study, we conducted a comprehensive multiomic analysis of fertile and abortive ovules and found that ACS genes in chestnuts (CmACS) play a crucial role in ovule development. Therefore, to further study the function of ACS genes, a total of seven CmACS members were identified, their gene structures, conserved structural domains, evolutionary trees, chromosomal localization, and promoter cis-acting elements were analyzed, and their subcellular localization was predicted and verified. The spatiotemporal specificity of the expression of the seven CmACS genes was confirmed via qRT-PCR analysis. Notably, CmACS7 was exclusively expressed in the floral organs, and its expression peaked during fertilization and decreased after fertilization. The ACC levels remained consistently greater in fertile ovules than in abortive ovules. The ACSase activity of CmACS7 was identified using the genetic transformation of chestnut healing tissue. Micro Solanum lycopersicum plants overexpressing CmACS7 had a significantly greater rate of seed failure than did wild-type plants. Our results suggest that ovule fertilization activates CmACS7 and increases ACC levels, whereas an overexpression of CmACS7 leads to an increase in ACC content in the ovule prior to fertilization, which can lead to abortion. In conclusion, the present study demonstrated that chestnut ovule abortion is caused by poor fertilization and not by nutritional competition. Optimization of the pollination and fertilization of female flowers is essential for increasing chestnut yield and reducing ovule abortion.

The Mechanism of Ovule Abortion in Self-Pollinated 'Hanfu' Apple Fruits and Related Gene Screening.

Apples exhibit S-RNase-mediated self-incompatibility and typically require cross-pollination in nature. 'Hanfu' is a cultivar that produces abundant fruit after self-pollination, although it also shows a high rate of seed abortion afterwards, which greatly reduces fruit quality. In this study, we investigated the ovule development process and the mechanism of ovule abortion in apples after self-pollination. Using a DIC microscope and biomicroscope, we found that the abortion of apple ovules occurs before embryo formation and results from the failure of sperm-egg fusion. Further, we used laser-assisted microdissection (LAM) cutting and sperm and egg cell sequencing at different periods after pollination to obtain the genes related to ovule abortion. The top 40 differentially expressed genes (DEGs) were further verified, and the results were consistent with switching the mechanism at the 5' end of the RNA transcript (SMART-seq). Through this study, we can preliminarily clarify the mechanism of ovule abortion in self-pollinated apple fruits and provide a gene reserve for further study and improvement of 'Hanfu' apple fruit quality.

Strigolactones Might Regulate Ovule Development after Fertilization in Xanthoceras sorbifolium.

Strigolactones (SLs) were recently defined as a novel class of plant hormones that act as key regulators of diverse developmental processes and environmental responses. Much research has focused on SL biosynthesis and signaling in roots and shoots, but little is known about whether SLs are produced in early developing seeds and about their roles in ovule development after fertilization. This study revealed that the fertilized ovules and early developing pericarp in Xanthoceras sorbifolium produced minute amounts of two strigolactones: 5-deoxystrigol and strigol. Their content decreased in the plants with the addition of exogenous phosphate (Pi) compared to those without the Pi treatment. The exogenous application of an SL analog (GR24) and a specific inhibitor of SL biosynthesis (TIS108) affected early seed development and fruit set. In the Xanthoceras genome, we identified 69 potential homologs of genes involved in SL biological synthesis and signaling. Using RNA-seq to characterize the expression of these genes in the fertilized ovules, 37 genes were found to express differently in the fertilized ovules that were aborting compared to the normally developing ovules. A transcriptome analysis also revealed that in normally developing ovules after fertilization, 12 potential invertase genes were actively expressed. Hexoses (glucose and fructose) accumulated at high concentrations in normally developing ovules during syncytial endosperm development. In contrast, a low ratio of hexose and sucrose levels was detected in aborting ovules with a high strigolactone content. XsD14 virus-induced gene silencing (VIGS) increased the hexose content in fertilized ovules and induced the proliferation of endosperm free nuclei, thereby promoting early seed development and fruit set. We propose that the crosstalk between sugar and strigolactone signals may be an important part of a system that accurately regulates the abortion of ovules after fertilization. This study is useful for understanding the mechanisms underlying ovule abortion, which will serve as a guide for genetic or chemical approaches to promote seed yield in Xanthoceras.

Transcriptomic and Metabolic Profiling Reveal the Mechanism of Ovule Development in Castanea mollissima.

Ovule abortion, which is the main cause of empty burs in the Chinese chestnut, affects the formation of embryos and further reduces yield; therefore, it is important to study the mechanism of ovule abortion. In this study, we analyzed the transcriptomic and metabolomic data of ovules at critical developmental stages to explore the key regulatory networks affecting ovule development. The metabolites were enriched mainly in pathways involved in phytohormone signaling, energy metabolism, and amino acid synthesis in the endoplasmic reticulum. Analysis of the differentially expressed genes (DEGs) revealed that the HSP genes were significantly down-regulated during fertilization, indicating that this process is extremely sensitive to temperature. The hormone and sucrose contents of ovules before and after fertilization and of fertile and abortive ovules at different developmental stages showed significant differences, and it is hypothesized that that abnormal temperature may disrupt hormone synthesis, affecting the synthesis and catabolism of sucrose and ultimately resulting in the abortive development of Chinese chestnut ovules. At the pollination and fertilization stage of chestnuts, spraying with ethylene, ACC, and AIB significantly increased the number of developing fruit in each prickly pod compared to CK (water) treatment. These results indicated that both ethylene and ACC increased the rate of ovule development. This study provides an important theoretical molecular basis for the subsequent regulation of ovule development and nut yield in the Chinese chestnut.

Single-cell RNA-seq reveals a link of ovule abortion and sugar transport in Camellia oleifera.

Camellia oleifera is the most important woody oil crop in China. Seed number per fruit is an important yield trait in C. oleifera. Ovule abortion is generally observed in C. oleifera and significantly decreases the seed number per fruit. However, the mechanisms of ovule abortion remain poorly understood at present. Single-cell RNA sequencing (scRNA-seq) was performed using mature ovaries of two C. oleifera varieties with different ovule abortion rates (OARs). In total, 20,526 high-quality cells were obtained, and 18 putative cell clusters were identified. Six cell types including female gametophyte, protoxylem, protophloem, procambium, epidermis, and parenchyma cells were identified from three main tissue types of ovule, placenta, and pericarp inner layer. A comparative analysis on scRNA-seq data between high- and low-OAR varieties demonstrated that the overall expression of CoSWEET and CoCWINV in procambium cells, and CoSTP in the integument was significantly upregulated in the low-OAR variety. Both the infertile ovule before pollination and the abortion ovule producing after compatible pollination might be attributed to selective abortion caused by low sugar levels in the apoplast around procambium cells and a low capability of hexose uptake in the integument. Here, the first single-cell transcriptional landscape is reported in woody crop ovaries. Our investigation demonstrates that ovule abortion may be related to sugar transport in placenta and ovules and sheds light on further deciphering the mechanism of regulating sugar transport and the improvement of seed yield in C. oleifera.

Ovule abortion – a rivalry action or dispersal strategy?

Ovule abortion – a rivalry action or dispersal strategy?

Role of Micronutrients Towards Crop Productivity under Biotic and Abiotic Stresses: A Review

In recent scenarios, the world’s food system is highly insecure and become a great challenge to the rapidly growing civilization. Agriculture is intricately tied to food security and life sustainability on earth. The arising climatic alteration forces plants to compete for nutrients from the soil. Crop yielding and their nutritional quality are highly influenced by environmental factors (biotic and abiotic stress), agronomic factors, pests and nutrient availability in the soil. These are the nanoparticle that monitors the elements in soil by sharing some signals. Micronutrients help to maximize plant growth and protect plants from diseases and pathogens. But the alteration of the environmental condition is highly responsible for nutrient limitation and growth inhibition. 35% of the world’s agricultural lands are decreasing their soil fertility, which leads to nutrient deficiency in plants. These insufficient nutrients of crops lower the yield and nutritional quality of food and affected human health. In the reproductive stage of plant growth, environmental stress is highly responsible for flower drop, pollen tube deformation, ovule abortion, pollen sterility and yield losses. A sufficient quantity of micronutrients can help to reduce the biotic and abiotic stress in agricultural crops. The current review gives a brief knowledge to understand the current features of micronutrients in the agricultural crop which focus on the mechanism, absorption activity, toxicity and deficiency of micronutrients in plants and how it secures our food system by increasing the yield and nutritional quality.

Female Reproductive Potential and 3x by 2x Breeding Approach for Hybrid Seeds Development in Sukali Ndizi Genotype (Musa genome AAB)

Sukali Ndizi is one of the most popular local desert banana cultivars in Uganda. The crop is affected by a number of diseases and pests. Genetic improvement of the crop by hybridization may be hindered by very low seed set and poor seed germination. The main characteristics for assessing the female reproductive potential (seed set, seed quality and embryo germination of hybrid seeds) and 3x by 2x breeding approach were assessed in crosses of eleven different male diploid parents either wild or improved diploids with Sukali Ndizi landrace as the female parent for a period of 5 consecutive years planted in pollination blocks at National Agricultural Research Laboratories Kawanda (NARL). The month of pollination did not show any pattern throughout the pollination period but the crosses showed considerable variability in seed set, seed quality, and seed germination for different male diploids used. The water gravity test which differentiated the extracted seeds as sunken/viable and floating/nonviable seeds showed that a substantial amount of seed was floating and the sunken externally characterized by black hard integuments was only 39% with a range = 24%–60% which contained embryos, of which 22% (range = 0–37%) germinated. The increase in non-viable seed suggested that ovule abortion in Sukali Ndizi which mainly involved embryo and endosperm abortions was the cause of limited seed germination and the paternity of the zygotes was a major factor underlying abortions. Flow cytometric analysis of nuclear DNA content was used to estimate ploidy levels of the progenies with results showing that using 3x by 2x breeding approach differing levels of ploidy were achieved [3x (288), 4x (61), 5x (14) and 2x (2)] signifying the predominance of 3x progenies and the presence of 5x and 4x conforming to the possibility of sexual polyploids. Although pollination of Sukali Ndizi can be done all around the year, the seed set both quantity and quality and germination were very poor, necessitating the development of an efficient regeneration protocol for zygotic embryos at varying maturity stages to increase the recovery of hybrids.

Ovule Number and Flower Size in Pea (Pisum sativum L.): Variation, Heritability, and Correlation with Some Components of Productivity

The seed yield in pea (Pisum sativum L.) depends on numerous environmental and genotypic factors. The ongoing climate changes draw one’s attention to genetics and variation of underexplored reproductive traits. This study focuses on ovule number (ON) and flower size expressed as a length of flag petal (FL), in terms of their heritability, variability, and correlation with 1000 seed mass (TSM), seed number per pod, and seed/ovule ratio. A set of pea accessions was planted over several years in field conditions. Some of these accessions were also grown in a glasshouse. The chosen values were scored on living plants or while harvesting seeds. Nonparametric statistical methods were applied. Heritability of ON and FL was studied in five hybrid F1/F2 combinations. We found a relatively low (ca. 0.5) broad sense heritability of both ON and FL. Among other traits, TSM and ON reproduced best over the years. FL exhibited no reproducible correlations with other traits and cannot be used as a predictor of productivity. Water deficit and heat stress reduce seed yield in pea due to both seed abortion and development of fewer ovules. The differential and heritable ability to retain ON may become a basis for breeding pea cultivars adapted to changing climate.

Ovary abortion in field-grown maize under water-deficit conditions is determined by photo-assimilation supply

Ovary abortion in field-grown maize under water-deficit conditions is determined by photo-assimilation supply

Transcriptome sequencing and gene expression analysis revealed early ovule abortion of Paeonia ludlowii

BackgroundPaeonia ludlowii (Stern & G. Taylor D.Y. Hong) belongs to the peony group of the genus Paeonia in the Paeoniaceae family and is now classified as a “critically endangered species” in China. Reproduction is important for this species, and its low fruiting rate has become a critical factor limiting both the expansion of its wild population and its domestic cultivation.ResultsIn this study, we investigated possible causes of the low fruiting rate and ovule abortion in Paeonia ludlowii. We clarified the characteristics of ovule abortion and the specific time of abortion in Paeonia ludlowii, and used transcriptome sequencing to investigate the mechanism of abortion of ovules in Paeonia ludlowii.ConclusionsIn this paper, the ovule abortion characteristics of Paeonia ludlowii were systematically studied for the first time and provide a theoretical basis for the optimal breeding and future cultivation of Paeonia ludlowii.

Ovule abortion and seed set of field pea (Pisum sativum L.) grown under high temperature

In pea, high temperatures during reproductive development lead to severe yield loss. Although the ovule is the seed precursor, studies elucidating the effect of heat on this plant structure are scarce. We investigated the impact of heat in the field and growth chamber on ovules 4 days after the open flower (4DOF) stage. Objectives were to identify associations between ovaries and plant performance, and to evaluate seed set and ovule abortion of heat-treated plants for six cultivars from a diverse range of seed-to-ovule ratios. In the field, plants were seeded at early (control, [early seeded pea, ESP]) and late (stress plant [late seeded pea, LSP]) periods in the season. In growth chambers, plants were exposed to heat (35/18 °C) at early flowering for 4 days and then evaluated at maturity. Stressed plants (LSP) displayed twice as many aborted ovules than ESP during early embryo growth (pro-embryo to globular stage) in synchrony with reduced ovaries, ovules, and embryo sac size. Cultivars with reduced ovary size at 4DOF were related to a high number of reproductive nodes and pods in LSP ( r = −0.44 to −0.48). Similarly, under growth chamber conditions, heat caused seed reduction by increasing the abortion of immature ovules (early embryonic stages) at various reproductive nodes. Collectively, our results indicated that pea seed loss from heat in the field is largely due to early embryo abortion, a novel finding, rather than disruption of pre-fertilization events. Compensatory effects on plant performance infer plant resource adjustment. Our findings contribute to the assessment and selection of high-yielding pea cultivars for future warming seasons.

Horticultural Practices in Early Spring to Mitigate the Adverse Effect of Low Temperature on Fruit Set in 'Lapins' Sweet Cherry.

Yield of sweet cherry (Prunus avium L.) is determined by fruit set, a developmental stage sensitive to variable spring environmental conditions. To sustain fruit production and enhance crop climate resilience, it is important to understand the impacts of abiotic stresses and the effectiveness of horticultural mitigations in the spring on the critical developmental processes during fruit set. In this study, flowering phenology, pistil browning and percent fruit set of 'Lapins' were monitored at five sites of different elevation and frost risk in the Okanagan Valley, British Columbia, Canada, in 2019 and 2022. At Site 1 in Summerland Research and Development Centre ("SuRDC1"), where a 'Lapins' on Krymsk 5 planting was located in a frost pocket where the crops were exposed to high risk of cold damage in the spring, a series of experiments were conducted to investigate the floral organ viability and percent fruit set under low temperatures, and under the effects of four spring horticultural mitigation measures. Installation of polyethylene sleeves and FAME spray (fatty acid methyl esters-based plant growth regulator, WAIKEN, SST Australia) were implemented in 2019; boric acid spray and postponed irrigation were tested in 2022. Low fruit set at SuRDC1 in both years was associated with severe pistil browning after night temperature dropped below -4 °C in late April. In 2019, the semi-enclosure of polyethylene sleeves led to an increase in the surface temperature (Tsurfae) of floral buds by 2-4 °C, which prolonged the stage of first bloom, delayed petal fall and prevented frost damage on pistils, but led to the decrease in percent fruit set by 77%, due to ovule abortion or cessation of fruitlet development. The early and late sprays of FAME had no significant influence on either abundance of germinated pollen tubes or percent fruit set; however, the potential of late spray in improving pollen abundance and reducing pistil browning requires further investigation. In 2022, the spray of 0.01% boric acid solution led to a decrease in fruit set by 6.95%. Six-week postponement of irrigation starting from full bloom decreased soil moisture, but increased soil temperature and improved fruit set by 7.61%. The results improved our understanding about the damages of adverse spring air temperatures on pistils and ovules, and suggested the potential of irrigation adjustment in regulating soil moisture and temperature and improving fruit set in the cool and moist spring.

Improvement of RNA In Situ Hybridisation for Grapevine Fruits and Ovules.

The European grapevine (Vitis vinifera L.) is one of the world's most widely cultivated and economically important fruit crops. Seedless fruits are particularly desired for table grapes, with seedlessness resulting from stenospermocarpy being an important goal for cultivar improvement. The establishment of an RNA in situ hybridisation (ISH) system for grape berries and ovules is, therefore, important for understanding the molecular mechanisms of ovule abortion in stenospermocarpic seedless cultivars. We improved RNA in situ hybridisation procedures for developing berries and ovules by targeting two transcription factor genes, VvHB63 and VvTAU, using two seeded varieties, 'Red Globe' and 'Pinot Noir', and two seedless cultivars, 'Flame Seedless' and 'Thompson Seedless'. Optimisation focused on the time of proteinase K treatment, probe length, probe concentration, hybridisation temperature and post-hybridisation washing conditions. The objectives were to maximise hybridisation signals and minimise background interference, while still preserving tissue integrity. For the target genes and samples tested, the best results were obtained with a pre-hybridisation proteinase K treatment of 30 min, probe length of 150 bp and concentration of 100 ng/mL, hybridisation temperature of 50 °C, three washes with 0.2× saline sodium citrate (SSC) solution and blocking with 1% blocking reagent for 45 min during the subsequent hybridisation. The improved ISH system was used to study the spatiotemporal expression patterns of genes related to ovule development at a microscopic level.

Why honeybees are poor pollinators of a mass-flowering plant: Experimental support for the low pollen quality hypothesis.

PremiseHoneybees dominate the flower‐visitor assemblages of many plant species, yet their efficiency in terms of the quality of pollen delivered to stigmas is largely unknown. We investigated why honeybees are poor pollinators of Aloe ferox, a self‐incompatible succulent treelet with large numbers of flowers. Honeybees are very frequent visitors to flowers of this species, yet contribute very little to seed production.MethodsWe assessed pollen loads on honeybees, studied their visitation behavior, selectively excluded birds from plants to determine direct effects of bees on pollen deposition, seed set, and ovule abortion, and used a novel “split‐pollinator” method to test whether honeybees deposit mainly low‐quality self pollen. For the latter, we captured honeybees, and with their existing pollen loads, used them to either pollinate virgin flowers on the plant on which they were caught or to pollinate virgin flowers on different plants.ResultsHoneybees cumulatively deposit as much pollen on stigmas as do birds, but our experiments showed that the pollen deposited by honeybees is mostly low‐quality self pollen that leads to substantial ovule discounting and depressed seed set.ConclusionsLack of movement among A. ferox plants during individual honeybee foraging bouts is the most likely explanation for their deposition of low‐quality self pollen on stigmas. The “split‐pollinator” method is a simple and cost‐effective technique to test the quality of pollination.

Plant Nutrition: An Effective Way to Alleviate Abiotic Stress in Agricultural Crops.

By the year 2050, the world’s population is predicted to have grown to around 9–10 billion people. The food demand in many countries continues to increase with population growth. Various abiotic stresses such as temperature, soil salinity and moisture all have an impact on plant growth and development at all levels of plant growth, including the overall plant, tissue cell, and even sub-cellular level. These abiotic stresses directly harm plants by causing protein denaturation and aggregation as well as increased fluidity of membrane lipids. In addition to direct effects, indirect damage also includes protein synthesis inhibition, protein breakdown, and membranous loss in chloroplasts and mitochondria. Abiotic stress during the reproductive stage results in flower drop, pollen sterility, pollen tube deformation, ovule abortion, and reduced yield. Plant nutrition is one of the most effective ways of reducing abiotic stress in agricultural crops. In this paper, we have discussed the effectiveness of different nutrients for alleviating abiotic stress. The roles of primary nutrients (nitrogen, phosphorous and potassium), secondary nutrients (calcium, magnesium and sulphur), micronutrients (zinc, boron, iron and copper), and beneficial nutrients (cobalt, selenium and silicon) in alleviating abiotic stress in crop plants are discussed.

Characterizing plant trait(s) for improved heat tolerance in field pea (Pisum sativum L.) under subtropical climate.

Field pea is highly sensitive to climatic vagaries, particularly high-temperature stress. The crop often experiences terminal heat stress in tropical climates indicating the need for the development of heat-tolerant cultivars. Characterization and identification of stress-adaptive plant traits are pre-requisites for breeding stress-tolerant/adaptive cultivar(s). In the study, a panel of 150 diverse field pea genotypes was tested under three different temperature environments (i.e., normal sowing time or non-heat stress environment (NSTE), 15days after normal sowing time or heat stress environment-I (LSHTE-I), and 30days after normal sowing time or heat stress environment-II (LSHTE-II)) to verify the effect of high-temperature environment, genotype, and genotype × environment interaction on different plant traits and to elucidate their significance in heat stress adaptation/tolerance. The delayed sowing had exposed field pea crops to high temperatures during flowering stage by + 3.5°C and + 8.1°C in the LSHTE-I and LSHTE-II, respectively. Likewise, the maximum ambient temperature during the grain-filling period was + 3.3°C and + 6.1°C higher in the LSHTE-I and LSHTE-II over the NSTE. The grain yield loss with heat stress was 25.8 ± 2.2% in LSHTE-I, and 59.3 ± 1.5% in LSHTE-II compared to the NSTE. Exposure of crops to a high-temperature environment during the flowering stage had a higher impact on grain yield than the heat stress at the grain filling period. Results suggested that the reduced sink capacity (pod set (pod plant-1), seed set (seed pod-1)) was the primary cause of yield loss under the heat stress environments, while, under the NSTE, yield potential was mostly attributed to the source capacity (plant biomass). The high-temperature stress resulted in forced maturity as revealed by shrinkage in crop period (5-11%) and reproductive period (15-36%), prominently in long-duration genotypes. The failure of pod set in the upper nodes and higher ovule abortion (7-16%) was noticed under the high-temperature environments, particularly in the LSHTE-II. Multivariate analysis results revealed seed set, pods plant-1, last pod bearing node, and plant biomass as a critical yield determinant under the heat stress. The GGE biplot suggested that the genotypes G-112, G-114, and G-33 had higher potential to sustain yield coupled with higher stability across the environments and, thus, could serve as a source for breeding heat-tolerant high yielding cultivars.

Expression characterization and cross-species complementation uncover the functional conservation of YABBY genes for leaf abaxial polarity and carpel polarity establishment in Saccharum spontaneum

BackgroundCell polarity establishment and maintenance is indispensable for plant growth and development. In plants, the YABBY transcription factor family has a distinct role in leaf asymmetric polarity establishment and lateral organ initiation. However, for the important sugar crop Saccharum, little information on YABBY genes is available.ResultsIn this study, a total of 20 sequences for 7 SsYABBY genes were identified in the sugarcane genome, designated as SsYABBY1-7 based on their chromosome locations, and characterized by phylogenetic analysis. We provided a high-resolution map of SsYABBYs’ global expression dynamics during vegetative and reproductive organ morphogenesis and revealed that SsYABBY3/4/5 are predominately expressed at the seedling stage of stem and leaf basal zone; SsYABBY2/5/7 are highly expressed in ovules. Besides, cross-species overexpression and/or complementation verified the conserved function of SsYABBY2 in establishing leaf adaxial-abaxial polarity and ovules development. We found that the SsYABBY2 could successfully rescue the leaves curling, carpel dehiscence, and ovule abortion defects in Arabidopsis crc mutant.ConclusionsCollectively, our study demonstrates that SsYABBY genes retained a conserved function in establishing and preserving leaf adaxial-abaxial polarity and lateral organ development during evolution.