RESUMO
Cocos nucifera L. is a crop grown in the humid tropics. It is grouped into two classes of varieties: dwarf and tall; regardless of the variety, the endosperm of the coconut accumulates carbohydrates in the early stages of maturation and fatty acids in the later stages, although the biochemical factors that determine such behavior remain unknown. We used tandem mass tagging with synchronous precursor selection (TMT-SPS-MS3) to analyze the proteomes of solid endosperms from Yucatan green dwarf (YGD) and Mexican pacific tall (MPT) coconut cultivars. The analysis was conducted at immature, intermediate, and mature development stages to better understand the regulation of carbohydrate and lipid metabolisms. Proteomic analyses showed 244 proteins in YGD and 347 in MPT; from these, 155 proteins were shared between both cultivars. Furthermore, the proteomes related to glycolysis, photosynthesis, and gluconeogenesis, and those associated with the biosynthesis and elongation of fatty acids, were up-accumulated in the solid endosperm of MPT, while in YGD, they were down-accumulated. These results support that carbohydrate and fatty acid metabolisms differ among the developmental stages of the solid endosperm and between the dwarf and tall cultivars. This is the first proteomics study comparing different stages of maturity in two contrasting coconut cultivars and may help in understanding the maturity process in other palms.
Assuntos
Cocos , Endosperma , Endosperma/metabolismo , Cocos/metabolismo , Ácidos Graxos/metabolismo , Proteoma/metabolismo , Proteômica , Carboidratos , Redes e Vias MetabólicasRESUMO
MAIN CONCLUSION: Blue light exposure delays tomato seed germination by decreasing endosperm-degrading hydrolase activities, a process regulated by CRY1a-dependent signaling and the hormonal balance between ABA and GA. The germination of tomato seeds (Solanum lycopersicum L.) is tightly controlled by an internal hormonal balance, which is also influenced by environmental factors such as light. In this study, we investigated the blue light (BL)-mediated impacts on physiological, biochemical, and molecular processes during the germination of the blue light photoreceptor CRYPTOCHROME 1a loss-of-function mutant (cry1a) and of the hormonal tomato mutants notabilis (not, deficient in ABA) and procera (pro, displaying a GA-constitutive response). Seeds were germinated in a controlled chamber in the dark and under different intensities of continuous BL (ranging from 1 to 25 µmol m-2 s-1). In general, exposure to BL delayed tomato seed germination in a fluency rate-dependent way due to negative impacts on the activities of endosperm-degrading hydrolases, such as endo-ß-mannanase, ß-mannosidase, and α-galactosidase. However, not and pro mutants presented higher germination speed index (GSI) compared to WT despite the BL influence, associated with higher hydrolase activities, especially evident in pro, indicating that the ABA/GA hormonal balance is important to diminish BL inhibition over tomato germination. The cry1a germination percentage was higher than in WT in the dark but its GSI was lower under BL exposure, suggesting that functional CRY1a is required for BL-dependent germination. BL inhibits the expression of GA-biosynthetic genes, and induces GA-deactivating and ABA-biosynthetic genes. The magnitude of the BL influence over the hormone-related transcriptional profile is also dependent upon CRY1a, highlighting the complex interplay between light and hormonal pathways. These results contribute to a better understanding of BL-induced events behind the photoregulation of tomato seed germination.
Assuntos
Endosperma , Solanum lycopersicum , Endosperma/genética , Endosperma/metabolismo , Solanum lycopersicum/genética , Germinação , Sementes/fisiologia , Criptocromos/genética , Criptocromos/metabolismo , beta-Manosidase/genética , beta-Manosidase/metabolismo , Percepção , Ácido Abscísico/metabolismo , Giberelinas/metabolismo , Regulação da Expressão Gênica de PlantasRESUMO
Ananas ananassoides (Baker) L.B.Sm. is a wild pineapple, commonly found in the savannas. This study aimed to describe the morpho-anatomy and histochemistry of its seed. The observations were made in the longitudinal and transverse sections, using an optical microscope. The cell arrangement in the seed coat, ripples in the integument, the ratio of embryo size and endosperm amount, and the number of strata in the aleurone layer are anatomical characteristics that may contribute to distinguishing this species. The starch in the endosperm, lipids and proteins in the embryo, constitute the seed's main nutritional reserves. The homogeneous embryo and phenolic compounds present in the seed coat and in the aleurone layer possibly contribute to the dormancy in this species. This study presents information relevant to the taxonomy and physiology of A. ananassoides, which represents contributions to the global knowledge of this species with a high potential as ornamental.
Assuntos
Ananas , Endosperma/metabolismo , Pradaria , Sementes/químicaRESUMO
BACKGROUND: Protein percentage and kernel weight affect the endosperm hardness of maize grains. However, changes in starch composition could also modify kernel hardness, which is often predicted through milling ratio. The objective of this work was to evaluate the relationship between changes in starch composition and endosperm hardness, and to assess the effects of protein content and kernel weight on that relationship. For this, we used information obtained from three temperate hybrids in multi-environmental experiments, as well as experiments conducted under controlled conditions designed to modify starch composition. Milling ratio was determined as maize kernel hardness predictor in both experiments and it was correlated with grain weight and grain composition. RESULTS: In both experiments, milling ratio presented a significant Spearman correlation coefficient with amylose/starch ratio. Milling ratio was significantly related to the amylose/starch ratio using a simple fit with datasets from different experiments and hybrids. Increases in amylose/starch ratio were associated with increases in milling ratio. CONCLUSION: Starch composition was related to milling ratio variations among hybrids of different aptitude for dry milling through different environments, regardless of protein content. Thus, increases in the amylose/starch ratio were related to increases in the milling ratio. © 2022 Society of Chemical Industry.
Assuntos
Amido , Zea mays , Amilose/metabolismo , Endosperma/metabolismo , Dureza , Amido/química , Zea mays/químicaRESUMO
The role of the cotyledonary haustorium (CH) in the mobilization of nutrient reserves in the endosperm of species of the palm family Arecaceae is a moot question. To shed light on this matter, we present here an analysis of the quantitative proteome changes associated with four developmental stages of CH and three of endosperm during germination. Together, a total of 1965 proteins were identified, being 1538 in the CH and 960 in the endosperm. Both in the CH and endosperm proteomes, we observed an increase in the diversity of hydrolases as the CH and endosperm develops. Qualitative proteomics analysis of four CH developmental stages indicated that each stage is populated by a unique set of proteins and the quantitative analysis showed an increase in the relative abundance of hydrolases, particularly mannan degrading enzymes, as development progresses. These results add weight to the hypothesis that the CH in the seeds of E. oleraceaacts both as a conduit of carbon and nitrogen sources generated by the hydrolysis of the reserves in the endosperm and as a source of hydrolases that will contribute to the mobilization of these reserves.
Assuntos
Euterpe/fisiologia , Germinação/genética , Proteínas de Plantas/metabolismo , Proteoma/metabolismo , Sementes/crescimento & desenvolvimento , Cotilédone/metabolismo , Endosperma/metabolismoRESUMO
Calcium is a secondary messenger that regulates and coordinates the cellular responses to environmental cues. Despite calcium being a key player during fertilization in plants, little is known about its role during the development of the endosperm. For this reason, the distribution, abundance, and dynamics of cytosolic calcium during the first stages of endosperm development of Agave tequilana and Agave salmiana were analyzed. Cytosolic calcium and actin filaments detected in the embryo sacs of Agave tequilana and A. salmiana revealed that they play an important role during the division and nuclear migration of the endosperm. After fertilization, a relatively high concentration of cytosolic calcium was located in the primary nucleus of the endosperm, as well as around migrating nuclei during the development of the endosperm. Cytosolic calcium participates actively during the first mitosis of the endosperm mother cell and interacts with the actin filaments that generate the motor forces during the migration of the nuclei through the large cytoplasm of the central cell.
Assuntos
Agave/crescimento & desenvolvimento , Cálcio/metabolismo , Citosol/metabolismo , Endosperma/crescimento & desenvolvimento , Citoesqueleto de Actina/metabolismo , Agave/citologia , Agave/metabolismo , Endosperma/citologia , Endosperma/metabolismo , Mitose , Células Vegetais/metabolismoRESUMO
Coconut is a crop that is economically important in several countries throughout the world. Unfortunately, production is decreasing because palms are affected by very serious phytoplasma diseases, such as lethal yellowing, and also most of coconuts are already very old. On the other hand, markets for coconut products have been rapidly growing in recent years. Hence, replanting of most cultivation surface worldwide, as well as establishing new surface, is urgently needed. This is an immense task, requiring at least a billion coconut palms that cannot be accomplished by traditional propagation through seed. Therefore the biotechnological alternative of micropropagation by somatic embryogenesis is needed. Research has been carried out on this subject in laboratories in several countries studying different approaches, testing different types of explants. The most responsive tissue has been plumule from zygotic embryos. A protocol for micropropagation of coconut based on plumule explants is described here. It involves the use of different media that are based on Y3 medium complemented with activated charcoal, gelling agent, sucrose, and growth regulators. These media allow the formation of embryogenic callus and somatic embryos, growth of shoots, and development of plantlets.
Assuntos
Cocos/crescimento & desenvolvimento , Técnicas de Embriogênese Somática de Plantas/métodos , Cocos/embriologia , Meios de Cultura , Endosperma/metabolismo , Zigoto/metabolismoRESUMO
The endosperm is a transitory structure involved in proper embryo elongation. The cell walls of mature seed endosperm are generally composed of a uniform distribution of cellulose, unesterified homogalacturonans, and arabinans. Recent studies suggest that changes in cell wall properties during endosperm development could be related to embryo growth. The degree of methyl esterification of homogalacturonans may be involved in this endosperm tissue remodelling. The relevance of the degree of homogalacturonan methyl esterification during seed development was determined by immunohistochemical analyses using a panel of probes with specificity for homogalaturonans with different degrees of methyl esterification. Low-esterified and un-esterified homogalacturonans were abundant in endosperm cells during embryo bending and were also detected in mature embryos. BIDXII (BDX) could be involved in seed development, because bdx-1 mutants had misshapen embryos. The methyl esterification pattern described for WT seeds was different during bdx-1 seed development; un-esterified homogalacturonans were scarcely present in the cell walls of endosperm in bending embryos and mature seeds. Our results suggested that the degree of methyl esterification of homogalacturonans in the endosperm cell wall may be involved in proper embryo development.
Assuntos
Arabidopsis/embriologia , Arabidopsis/fisiologia , Endosperma/embriologia , Endosperma/metabolismo , Pectinas/metabolismo , Sementes/fisiologia , Proteínas de Arabidopsis/metabolismo , Proteínas de Transporte/metabolismo , Desenvolvimento Embrionário/fisiologia , EsterificaçãoRESUMO
Annonaceous acetogenins (ACGs) are molecules with carbon numbers C35-C37, usually with tetrahydrofuran and tetrahydropyran rings and one terminal γ-lactone (usually α,ß-unsaturated), in a large aliphatic chain that is varyingly hydroxylated, acetoxylated or ketonized. ACGs have ecological functions as insecticides and are pharmacologically promising due to their cytotoxic and antitumoral properties. They are found in the seeds, leaves, roots, flowers and fruits of annonaceous plants and can be detected during isolation via thin-layer chromatography using Kedde's reagent, which reacts with the unsaturated lactone. This chapter describes the location in situ of ACGs in fresh sections of annonaceous seeds using Kedde's reagent.The acetogenins are located in the idioblasts, in the endosperm and in the embryonic axis during differentiation. This method can aid in the detection of ACGs with a terminal unsaturated γ-lactone in organs and tissues.
Assuntos
Acetogeninas/metabolismo , Histocitoquímica/métodos , Endosperma/citologia , Endosperma/metabolismo , Germinação , Sementes/metabolismoRESUMO
Coffee seeds begin to develop shortly after fertilization and can take 6 to 8 months to complete their formation, a period during which all the characteristics of the mature seed are determined, directly influencing physiological quality. However, little is known about the molecular mechanisms that act during coffee seed maturation. The objective of the current study was to analyze expression of the ß-tubulin (TUB) and endo-ß-mannanase (MAN) genes during different phases at the end of development and in different tissues of Coffea arabica seeds. The transcription levels of the TUB and MAN genes were quantified in a relative manner using qRT-PCR in whole seeds, and dissected into embryos and endosperms at different developmental stages. Greater expression of MAN was observed in whole seeds and in endosperms during the green stage, and in the embryo during the over-ripe stage. High TUB gene expression was observed in whole seeds during the green stage and, in the embryos, there were peaks in expression during the over-ripe stage. In endosperms, the peak of expression occurred in both the green stage and in the cherry stage. These results suggest participation of endo-ß-mannanase during the initial seed developmental stages, and in the stages of physiological maturity in the embryo tissues. TUB gene expression varied depending on the developmental stage and section of seed analyzed, indicating the participation of ß-tubulin during organogenesis and coffee seed maturation.