Discovery of UPSTREAM of FLOWERING LOCUS C (UFC) and FLOWERING LOCUS C EXPRESSOR (FLX) in Gladiolus ×Hybridus, G. Dalenii

Background. Gladiolus is a geophytic floricultural crop cultivated for cut flower and garden ornamental uses. Monocotyledonous flower crops have few, if any, flowering genes identified. Ornamental geophytes such as gladiolus, lily, tulip and daffodil are examples of floral crops that are currently being investigated to understand the flowering pathway. While the flower genes and environmental / hormonal factors leading to flowering are established in Arabidopsis, the lack of identified flowering genes in economically important ornamental geophytic crops, such as gladiolus, is critical to further genetic research. Thus, the importance of such an ornamental crop that relies on flowers (flowering) for economic purposes encourages researchers to discover the flowering genes to breed vigorous, flowering cultivars. The understanding of the flowering mechanisms in the flowering pathway is also of paramount importance. Results. Herein we show the discovery of UPSTREAM OF FLOWERING LOCUS C (UFC) and FLOWERING LOCUS C EXPRESSOR (FLX) genes in Gladiolus ×hybridus and G. dalenii. The UFC gene is adjacent to FLOWERING LOCUS C (FLC) which is a floral repressor in many temperate species. The FLX gene upregulates FRIGIDA (FRI) which upregulates FLC expression. Discovery of both genes is a step forward in finding the FLC gene in gladiolus, provided they are linked. Seventeen gladiolus genotypes, consisting of early flowering and commercial cultivars, were discovered to possess the UFC gene, consisting of four exons in two allelic forms. The sequenced UFC gene, when translated into its amino acid sequence and set in pair-alignment to other species, has up to 57% in amino acid identity to Musa acuminata. The UFC protein ranges in identity with pair-alignment to other monocot species, also with 57% amino acid identity to M. acuminata. The FLX gene in gladiolus has 3/5 (60%) exons in common relative to Ananas comosus, i.e. lacking 2 exons and a partially complete gene sequence; the pair-alignment of the three exons shows an overall ~65% identity of FLX to A. comosus. The UFC protein consists of a conserved domain, DUF966, which is higher in identity (86%) and pair-alignment with Elaeis guineensis. Conclusions. The two newly-discovered genes in gladiolus, UFC and FLX, provide insight to further our understanding of the flowering mechanism, flowering pathway genes, and vernalization response in ornamental geophytes. This knowledge will be valuable for gladiolus breeders and geneticists to finding the FLC gene, identify segregating seedlings for both UFC and FLX, and aid in marker assisted selection for flowering gene expression.

Discovery of UPSTREAM OF FLOWERING LOCUS C (UFC) and FLOWERING LOCUS C EXPRESSOR (FLX) in Gladiolus ×hybridus, G. dalenii

Gladiolus is a geophytic floricultural crop, cultivated for cut flower and garden ornamental uses. Ornamental geophytes such as gladiolus, lily, tulip and daffodil are examples of floral crops that are currently being investigated to understand the flowering pathway. While the environmental and hormonal factors leading to flowering are established in Arabidopsis. However, the lack of genetic regulation is poorly understood. Thus, the importance of such an ornamental crop that relies on flowers (flowering) for economic purposes encourages researchers to discover the flowering genes to breed vigorous flowering cultivars. The understanding of the flowering mechanisms in the flowering pathway is also paramount. Herein we show the discovery of UPSTREAM OF FLOWERING LOCUS C (UFC) and FLOWERING LOCUS C EXPRESSOR (FLX) genes in Gladiolus ×hybridus and G. dalenii. The UFC gene is adjacent to FLOWERING LOCUS C (FLC) which is a floral repressor in many temperate species. FLX gene upregulates FRIGIDA (FRI) which upregulates FLC expression. The discovery of both genes is a step forward in finding the FLC gene in gladiolus, provided they are linked. Seventeen gladiolus genotypes, consisting of early flowering and commercial cultivars, have the UFC gene, consisting of four exons in two allelic forms. The UFC gene sequenced when translated into amino acid sequence and set in pair-alignment to other species, has up to 57% in amino acid identity to Musa acuminata. The UFC protein ranges in identity with pair-alignment to other species, reaching up to 57% in amino acid identity to Musa acuminata. The FLX gene in gladiolus has 3/5 (60%) exons in relative to Ananas comosus, i.e. lacking 2 exons and a partially complete gene sequence; the pair-alignment of the three exons shows up over all ~65% identity of FLX to Ananas comosus. The UFC protein consists of a conserved domain, DUF966, which is higher in identity and pair-alignment, with up to 86% identity in Elaeis guineensis. The discovered FLX gene in gladiolus has 3/5 (60%) exons, i.e. lacking 2 exons and a partially complete gene sequence; the pair-alignment of the 3 exons shows up to ~65% of identity of FLX to Ananas comosus. These discovered two genes in gladiolus provide insight to further our understanding of the flowering and vernalization response in ornamental geophytes.

Antagonism between abscisic acid and gibberellin regulates starch synthesis and corm development in Gladiolus hybridus

Understanding corm development in flower bulbs is of importance for securing the quality of cut flowers and propagation of commercial stocks. Gladiolus is one of the most popular bulb plants worldwide. Its corm development is characterized by starch accumulation. Previous research has shown that phytohormones (especially gibberellin (GA)) are involved in tuber development. However, the relationship between abscisic acid (ABA)/GA and starch during corm development remains unclear. To gain deeper insights into the biological process of corm development, we performed a detailed anatomical characterization of different stages of corm development and analyzed phytohormone levels. Our study showed that corm development is linked to hormones (ABA and GA) and carbohydrates (sucrose and starch). Exogenous hormone treatment and silencing of endogenous hormone biosynthesis genes indicated that ABA positively regulates corm development, while GA acts as an antagonist of ABA function. A sucrose synthase gene (GhSUS2) was shown to be involved in the antagonism between ABA and GA. GhSUS2 was upregulated by ABA and downregulated by GA. The increase in the transcript level of GhSUS2 coincided with the development of corm/cormels. Silencing of GhSUS2 repressed corm development and starch accumulation. In conclusion, we propose that GhSUS2, an essential enzyme in sucrose degradation, is differentially regulated by ABA and GA and controls corm development in Gladiolus.

PENGARUH KOMPOSISI MEDIA TANAM TERHADAP PERTUMBUHAN DAN HASIL TANAMAN BUNGA GLADIOL (Gladiolus hybridus L.)

Tujuan penelitian ini adalah untuk mengetahui pengaruh komposisi media tanam terhadap pertumbuhan dan hasil bunga Gladiol serta menentukan komposisi yang paling baik dalam mendukung pertumbuhan dan perolehan hasil bunga. Penelitian dilakukan melalui percobaan menggunakan Rancangan Acak Kelompok (RAK), dengan 7 perlakuan komposisi media tanam yaitu P1 (tanah), P2 (tanah : arang sekam 1:1), P3 (tanah : arang sekam 1:2), P4 (tanah : arang sekam 2:1), P5 (tanah : cocopeat 1:1), P6 (tanah : cocopeat 1:2), P7 (tanah : cocopeat 2:1). Masing masing perlakuan ada dalam setiap kelompok yang sekaligus sebagai ulangan yang berjumlah 4 kelompok. Parameter yang diamati meliputi parameter fisik dan kimia media tanam yang terdiri dari pH, kadar air, dan NPK tersedia. Parameter pertumbuhan tanaman diamati melalui parameter tinggi tanaman dan jumlah daun serta hasil tanaman diamati melalui parameter jumlah bunga dan diameter bunga. Hasil penelitian menunjukkan bahwa komposisi media tanam tidak mempengaruhi tinggi tanaman dan jumlah daun, tetapi mempengaruhi jumlah bunga dan diameter bunga. Media tanam yang memberikan hasil terbaik adalah media tanah (P1) dengan jumlah bunga sebanyak 11.67 kuntum dan diameter bunga sebesar 13.62 cm.Kata Kunci: arang sekam, cocopeat, gladiol

Biological Features of Gladiolus hybridus in Connection with the Adaptation of the Siberian Region

The adaptive possibilities of the varietal diversity of Gladiolus hybridus in the forest-steppe zone of Western Siberia are analyzed. Morphobiological features of shoot formation are shown. Long-term (1999–2019) results of seasonal development of plants in generative age state are presented. The specificity of the terms of flowering varies from different groups of the sum of positive temperatures. Flowering in Novosibirsk occurs in early varieties with the sum of positive temperatures >1462° C, medium >1558° C, late >1711° C. It was determined that in the prewinter the cone of growth of the shoot of renewal forms rudimentary vegetative organs, which corresponds to the second stage of organogenesis. Differentiation of the cone of growth of escape to generative organs begins during the period of intensive growth of escape in June. During the period from 60–73 days, the cone of growth of the shoot passes intrarenal development from III to VIII stages of organogenesis. IX–XII stages of organogenesis correspond to the phenological stages from flowering to fruiting. Flowering duration is 10–25 days, seasonal development 118–123 days. There was a decrease in the coefficient of vegetative reproduction in varieties from 2015 to 2018 of 2–12 times. The main ecological niche of the pathogen Fusarium rot of gladiolus (of vosb. Fusarium oxysporum f. gladioli) are underground organs (roots, corms), and also-above-ground organs of plants. Comparison of the degree of resistance of gladiolus to Fusarium showed a different reaction of varieties during the growing season and storage of corms.