Gene regulation network analyses of pistil development in papaya

Background The pistil is an essential part of flowers that functions in the differentiation of the sexes and reproduction in plants. The stigma on the pistil can accept pollen to allow fertilization and seed development. Papaya (Carica papaya L.) is a dioecious plant, where female flowers exhibit normal pistil, while the male flowers exhibit aborted pistil at a late stage of pistil development. Results The developmental stages of papaya pistil were analyzed after first dividing it into slices representing the primordium stage 1 (S1), the pre-meiotic stages S2, post-meiotic stage S3, and the mitotic stage S4. The SS scoring algorithm analysis of genes preferentially expressed at different stages revealed differentially expressed genes between male and female flowers. A transcription factor regulatory network for each stage based on the genes that are differentially expressed between male and female flowers was constructed. Some transcription factors related to pistil development were revealed based on the analysis of regulatory networks such as CpAGL11, CpHEC2, and CpSUPL. Based on the specific expression of genes, constructed a gene regulatory subnetwork with CpAGL11-CpSUPL-CpHEC2 functioning as the core. Analysis of the functionally enriched terms in this network reveals several differentially expressed genes related to auxin/ brassinosteroid signal transduction in the plant hormone signal transduction pathway. At the same time, significant differences in the expression of auxin and brassinosteroid synthesis-related genes between male and female flowers at different developmental stages were detected. Conclusions The pistil abortion of papaya might be caused by the lack of expression or decreased expression of some transcription factors and hormone-related genes, affecting hormone signal transduction or hormone biosynthesis. Analysis of aborted and normally developing pistil in papaya provided new insights into the molecular mechanism of pistil development and sex differentiation in dioecious papaya.

Two New Species of Balanophora (Balanophoraceae) From South China

Abstract— Populations of Balanophora from southern China are often identified by local botanists as B. laxiflora based on their long cylindric male inflorescence, subsessile male flowers with slender rudimentary bracts, and subdiscoid synandria. In this study, we clarify the identity of seven such populations based on morphological characters and phylogenetic analysis using nuclear 18S and ITS ribosomal DNA sequences. We confirmed the occurrence of dioecious populations of B. yakushimensis and two previously unrecognized species, which we describe here as B. parajaponica and B. appressa. Phylogenetic analyses indicated that B. parajaponica, B. yakushimensis, B. appressa, B. laxiflora, and the agamospermic B. japonica, formed a well resolved clade, viz. the B. laxiflora clade. The four dioecious species, although highly similar in the morphology of male inflorescence and flowers, can be separated by leaf morphology and arrangement, ovary color, and arrangement of female flowers. The species limit of B. laxiflora, however, remains unresolved.

The Patterns of Male and Female Flowers in Flowering Stage May Not Be Optimal Resource Allocation for Fruit and Seed Growth

Changes in the proportions of male and female flowers in monoecious plants in response to external environmental conditions are directly related to the reproductive fitness of plants. The monoecious cucumber (Cucumber sativus) plant was used in this study to assess the responses of sex differentiation and the breeding process to nutrient supply and the degree of artificial pollination using pollen solutions of different concentrations. We found that the nutrient supply significantly improved the number of female flowers, while pollination treatments did not obviously increase the number of male flowers. Continuous pollination changed the number of female flowers especially in the later stage of the pollination experiment. Therefore, pollination changed the ratio of male and female flowers in the flowering stage of cucumber. Pollination treatment affected the fruit growth, seed set, and fruit yield. The number of fruit, fruit set percentage, and total seeds per plant did not increase with the pollination level, but individual fruit weight and seed number in one fruit did increase. The differentiation of male and female flowers in the flowering stage of cucumber is a response to nutrient and pollination resources, but this response is not the optimal resource allocation for subsequent fruit development and seed maturity, which suggests that the response of plants to external environment resources is short-term and direct.

Phenolic Compounds and Oxidative Enzymes Involved in Female Fertility in Banana Plants of the Cavendish Subgroup

The present study investigated phenolic compounds and enzymes involved in female fertility in banana plants of the Cavendish subgroup. The wild diploid Calcutta 4 and commercial cultivar Grand Naine (Cavendish subgroup) were used. The following five stages of floral development were proposed: S1 (partial vertical emission), S2 (total vertical emission), S3 (total horizontal emission), S4 (pre-anthesis), and S5 (anthesis). Following collection, pistillate (female) flowers were freeze-dried for the subsequent removal of nectaries and the analysis of phenolic compounds (PCs), antioxidant activity (DPPH and ABTS), enzymatic activity [peroxidase (POD) and polyphenol oxidase (PPO)], and total proteins (TPs). The highest values were recorded at the S3 stage, with the values decreasing as the stages progressed (until S5). At the S3 stage, the following results were obtained for Calcutta 4 and Grand Naine, respectively: PCs (32.4 and 36.1 mg GAE·g−1); DPPH (735.2 and 454.4 µM TE·g−1); ABTS (647.8 and 555.5 µM TE·g−1); POD (0.8 and 0.7 µmol·min−1·g−1); PPO (3.7 and 2.7 µmol·min−1·g−1); and TP (3.2 and 2.4 µmol·min−1·g−1). These results indicate that PCs and enzymes regulate female fertility, suggesting that crossbreeding should be performed from the S3 stage in cultivars of the Cavendish subgroup to achieve fruits with seeds.

Introduction of a New Interesting Walnut Cultivar “Leto”

Ιn an effort to create walnut cultivars (Juglans regia) with high productivity, fruit quality and lateral bearing, a new cultivar, named “Leto”, was created by the cross “Gustine” × “Pedro”. Its main phenological and pomological characteristics were assessed according to the criteria of IPGR (1994) and UPOV-TG/125/6 (1999), for 10 consecutive years and compared with its maternal cultivars and “Chandler”. Observations showed that “Leto” has high lateral bearing habit (90%) and presents satisfactory yield at the full production age. The tree size is smaller than that of its parents and “Chandler”, female flowers bloom from 11 to 22 of April and male from 3 to 6 of April. “Leto” nuts are harvested at the end of September, present easy hull dehiscence and high kernel percentage. Other positive nut characteristics of “Leto” are light kernel color, well kernel filling and easy removal of the kernel halves. “Leto” is a mid-early cultivar of great interest due to its high- quality nuts, suitable for dense plantings, in regions where the last spring frosts occur in late March to early April, thus, making it a promising cultivar for Greece, but also for other regions with similar geomorphological and climatic conditions.

VviPLATZ1 is a major factor that controls female flower morphology determination in grapevine

Plant genetic sex determinants that mediate the transition to dioecy are predicted to be diverse, as this type of mating system independently evolved multiple times in angiosperms. Wild Vitis species are dioecious with individuals producing morphologically distinct female or male flowers; whereas, modern domesticated Vitis vinifera cultivars form hermaphrodite flowers capable of self-pollination. Here, we identify the VviPLATZ1 transcription factor as a key candidate female flower morphology factor that localizes to the Vitis SEX-DETERMINING REGION. The expression pattern of this gene correlates with the formation reflex stamens, a prominent morphological phenotype of female flowers. After generating CRISPR/Cas9 gene-edited alleles in a hermaphrodite genotype, phenotype analysis shows that individual homozygous lines produce flowers with reflex stamens. Taken together, our results demonstrate that loss of VviPLATZ1 function is a major factor that controls female flower morphology in Vitis.

Annual variability in sound acorn production was regulated by a generalist seed predator weevil in Quercus serrata

Highly variable and synchronous seed production within a population (‘masting’) could be from either synchronised high annual variability in floral initiation (‘flower masting’) or synchronised floral abortion until maturity (‘fruit maturation masting’). We investigated the demographic processes of the female organs from flowering to seed maturity, including each type of insect damage identified, in Quercus serrata in six individuals within a stand from 2014 to 2020, western Japan. Although the annual production of sound acorns was significantly correlated with that of female flowers, the annual variability in sound acorn production within an individual was significantly higher and their synchrony increased, compared to those of female flowers. The annual production of female flowers was positively correlated with the temperature difference in April between the previous and flowering years. However, their fluctuation was low, which was neither affected by seed and flower production in the previous year nor contributed to predator starvation. Key-factor analyses revealed that reproductive loss due to oviposition and sap suction by Mechoris ursulus , a generalist seed predator weevil for oak species, was the largest and most important factor that contributed to the annual variation in the total pre-dispersal loss of Q. serrata . The survival rate from female flowers to sound acorns was strongly predicted by the temperature in June, corresponding to the emergence of adult M. ursulus . This study suggests that highly variable and synchronous sound seed production can be proximately regulated by seed predation when the main predator is a generalist.

Transcriptome-based analysis of the hormone regulation mechanism of gender differentiation in Juglans mandshurica Maxim

Juglans mandshurica Maxim is a hermaphroditic plant belonging to the genus Juglans in the family Juglandaceae. The pollination period of female flowers is different from the loose powder period of male flowers on the same tree. In several trees, female flowers bloom first, whereas in others, male flowers bloom first. In this study, male and female flower buds of J. mandshurica at the physiological differentiation stage were used. Illumina-based transcriptome sequencing was performed, and the quality of the sequencing results was evaluated and analyzed. A total of 138,138 unigenes with an average length of 788 bp were obtained. There were 8,116 differentially expressed genes (DEGs); 2,840 genes were upregulated, and 5,276 genes were downregulated. The DEGs were classified by Gene Ontology and analyzed by Kyoto Encyclopedia of Genes and Genomes. The signal transduction factors involved in phytohormone synthesis were selected. The results displayed that ARF and SAUR were expressed differently in the auxin signaling pathway. Additionally, DELLA protein (a negative regulator of gibberellin), the cytokinin synthesis pathway, and A-ARR were downregulated. On April 2nd, the contents of IAA, GA, CTK, ETH and SA in male and female flower buds of two types of J. mandshurica were opposite, and there were obvious genes regulating gender differentiation. Overall, we found that the sex differentiation of J. mandshurica was related to various hormone signal transduction pathways, and hormone signal transduction plays a leading role in regulation.

Effect of Ethephone, Zinc and Boron on growth and Yield of Cucumber (Cucumis Melo var. Flexuosus) Cultivated in Plastic Houses and The Economic Feasibility From That

A field experiment was carried out in one of the plastic houses belonging to the College of Agriculture, Al-Qasim green University to Studying the possibility of cultivating cucumis melo var. flexuosus inside greenhouses to improve growth and yield using microelements and ethephon. Microelements (Zn + B) at a concentration of 250 mg/L -1 and the growth regulator Elathyphon at a concentration of (2.5, 1.5, 0) ml/L -1 were used as a spray on the shoots. A factorial experiment was applied with the split plot system and randomized complete block design (RCBD) according to the least significant difference (L.S.D) test under the significance level of 0.05. The results were as follows: The interaction between (Zn + B) had a positive and significant effect on indicators such as leaf area 206.88 dm-1, number of female flowers 22.33flower-1, and the total yield 4327 kg, the percentage of nitrogen, phosphorous and potassium in the leaves was 0.6733, 2.691, 2.927, and the percentage of zinc and boron in the leaves was 19.626,14.282.The yield of one plant and the weight of the fruit 2575.5 g, 121.44 g, respectively. As for the interaction between Zn + B + 1.5, a significant effect on leaf area trait 239.91 Number of female flowers 26.33 flower-1, Total yield 5494 kg The percentage of PK in leaves 0.7233,3.080 and the percentage of boron in leaves 14.560 while the yield of one plant 3270.4 g