Strigo-D2 - a bio-sensor for monitoring the spatio-temporal pattern of strigolactone signaling in intact plants

Strigolactones (SLs) are a class of plant hormones modulating developmental programs in response to endogenous and exogenous stimuli and mediating biotic interactions. However, a comprehensive view on the spatio-temporal pattern of SL signaling has not been established and tools for a systematic in planta analysis do not exist. Here, we present Strigo-D2, a genetically encoded ratiometric SL signaling sensor, allowing the examination of SL signaling distribution with cellular resolution and its rapid response to altered SL levels in intact plants. By monitoring the abundance of a truncated and fluorescently labeled SUPPRESSOR OF MAX2 1-LIKE 6 (SMXL6) protein, a proteolytic target of the SL signaling machinery, we show that all cell types investigated have the capacity to respond to changes in SL levels but with very different dynamics. In particular, SL signaling is pronounced in vascular cells but low in guard cells and the meristematic region of the root. We also show that other hormones leave Strigo-D2 activity unchanged indicating that initial SL signaling steps work in isolation from other hormonal signaling pathways. Specificity and spatio-temporal resolution of Strigo-D2 underline the value of the sensor for monitoring SL signaling in a broad range of biological contexts and with highly instructive analytical depth.

PENGARUH UMUR EKSPLAN TERHADAP KEBERHASILAN PEMBENTUKAN KALUS EMBRIOGENIK PADA KULTUR MERISTEM JAHE (Zingiber officinale Rosc)

<p>ABSTRAK</p><p>Kendala dalam pengembangan jahe di Indonesia adalah terbatasnyabenih bermutu. Secara konvensional, budidaya jahe dilakukan denganmenggunakan bibit dari potongan rimpang. Dengan cara ini diperlukanbibit dalam jumlah yang banyak, antara 2-3 t/ha untuk jahe yang dipanentua dan 5-6 t/ha untuk yang dipanen muda. Kendala lain adalah penyakittular benih layu bakteri yang disebabkan oleh Ralstonia solanacearum.Salah satu upaya yang dapat dilakukan untuk mendapatkan benih jahebebas penyakit adalah perbanyakan melalui kultur jaringan. Penelitianbertujuan untuk mengkaji sumber eksplan dari tingkat umur panenrimpang yang berbeda terhadap kapasitas pembentukan kalus embriogenikpada kultur meristem jahe putih besar. Penelitian dilakukan di BalaiPenelitian Tanaman Obat dan Aromatik dari September 2007 sampaiMaret 2008, menggunakan rancangan acak lengkap dengan 20 kaliulangan. Bahan tanaman yang digunakan adalah meristem jahe putih besaryang diambil dari rimpang panen muda dan tua. Peubah yang diamatimeliputi: histologi jaringan, persentase kalus embriogenik yang terbentuk,bobot segar kalus, diameter kalus, dan morfologi kalus. Hasil penelitianmenunjukkan adanya daerah meristematik pada sayatan eksplan meristemjahe putih besar ukuran ± 0,25 cm. Persentase kalus embriogenik (92,1%)dan diameter kalus (0,59 mm) dari rimpang yang dipanen tua lebih tinggidari yang dipanen muda. Berat kalus (1,18 g) dan jumlah embrio somatikglobular (29,34) asal eksplan panen tua nyata lebih tinggi dari yangdipanen muda. Kalus embriogenik yang berasal dari eksplan rimpang yangdipanen tua mampu berkembang membentuk embrio somatik danberkecambah menghasilkan planlet normal.</p><p>Kata kunci : Zingiber officinale Rosc., umur rimpang, kalus embriogenik,embriogenesis somatik</p><p>ABSTRACT</p><p>Effect of explants age on the success of embryogenic calliformation in meristem culture of ginger (Zingiberofficinale Rosc.)</p><p>Constraint in ginger cultivation in Indonesia is the limited qualityof planting materials. In conventional cultivation, planting materials weretaken from a piece of rhizomes. By this technique, significant amount ofplanting materials is required, between 2-3 tons/ha for fully harvested and5-6 tons/ha for young harvested rhizomes. Another serious constraint isbacterial wilt disease infection caused by Ralstonia solanacearum. Effortfor obtaining free disease planting materials could be performed throughtissue culture mass propagation. In this study, different ages of rhizome asexplants sources was evaluated for their capacity in embryogenic calliformation on the meristem culture of ginger. The experiment wasconducted in Indonesian Medicinal and Aromatic Crops Research Institutefrom September 2007 to March 2008, using a completely random designwith 20 replicates. Plant material used was white ginger meristem takenfrom the fully and young harvested rhizomes. The observed variables wereexplant histology, percentage embryogenic calli formation (%), freshweight of calli, calli diameter, number of globular embryo, and callimorphology. The results showed a meristematic region at the incisionexplant big-white ginger meristem ± 0.25 cm in size. Percentage ofembryogenic calli formation from the fully harvested rhizome-explant(92.1%) and calli diameter (0.59 mm) were higher than that of the youngerone. Calli weight (1.18 g) and number of globular somatic embryos(29.34) from fully harvested rhizome-explants were significantly higherthan that of the younger one. Embriogenic calli derived from the oldharvested rhizome explants was able to grow well to form somaticembryos and then germinate to produce normal plantlet.</p><p>Key words : Zingiber officinale Rosc, age of rhizome, embriogeniccalli, somatic embryogenesis</p>

Studying on the in vitro shoot formation of Opuntia ficus – indica (L.) Mill.

This study presented the elimination of the glochids in the areoles of Opuntia ficus-indica cladode induced the shoot formation from the explants containing the shoot apical meristem (SAM) on Murashige and Skoog medium (MS) supplemented with 6-benzylaminopurine (BA) 5 mg/L. Morphological and physiological changes in shoot formation process were analyzed. This process involved the constant stages: activation of cell division, initiating of meristematic region; formation of shoot primordium and shoot with leaves. The SAM position in the upper front of the cladode gave the highest shoot productivity. This position had the photosynthesis rate, respiration rate, endogenous indole acetic acid (IAA) and zeatin activity higher than the others. Difference of auxin concentrations increased the amount of shoots and shoot height. The maximum number of shoots per explant was obtained on MS medium supplemented with BA 5 mg/L and 1-naphthalene acetic acid (NAA) 0.5 mg/L. The elimination of SAM by removing the surface of the shoot gave the highest number of the shoot. The correlation of the glochids in the areoles, explant position, plant hormones, photosynthesis rate respiration rate and shoot formation were discussed.

Somatic embryogenesis and callus formation in sugarcane (Saccharum SPP L.) using different concentration of 2, 4-D and RAPD analysis of plants regenerates

Present research was conduct to build up an efficient protocol for various concentrations of 2, 4-D for ”Callus formation and somatic embryogenesis in sugarcane (saccharin spp L.) Using various concentrations of 2, 4-D and RAPD analysis of regenerated plants in the Laboratory of Biotechnology Nuclear Institute of Agriculture Tandojam during the year 2013- 2014. Three sugarcane varieties Bl4, NIA-2010, NIA-2011 with various concentrations of 2, 4-D (0.5.1.0, 2.0, 3.0 and 4.0 mg l-1). While 3.0 mg l-1 Kin+IAA+IBA were used for callus proliferation and shoot formations. Four different concentration of IBA were used for rooting purpose 0.5, 1.0, 2.0 and 3.0 mgl-1+20 g Sugar. Embryonic callus was obtained by culturing young apical merited. Eight-month field grown three sugarcane clones via; BL4, NIA-2010 and NIA-2 011 we use for tissue culture somatic embryonic callus studies. The apical meristematic region was used for callus formation and somatic embryogenesis induction on 0.5, 1.0, 2.0, 3.0 and 4.0 mg l-1.2, 4-D actively growing callus was subcultured on kin.IAA, IBA, 3.0 mg l-1. Maximum callus proliferation and a number of plantlets shoot length and regeneration growth was observed in those plants that call taken from 1.0 and 2.0 mg l-1.2, 4-D Maximum chlorophyll mutation frequency was recorded in NIA-2010 and BL4 grown on 1.0 mg l-1 2, 4-D. The maximum number of roots was observed in BL4 when 1.0 mg l-1IBA+ 20% sugar was applied, variability obtained through callus culture and also confirmed through random amplified polymorphic DNA (RAPD) techniques.

Efeito da fonte de carbono na embriogênese somática em Bactris gasipaes

A metodologia de camada fina de células foi utilizada com sucesso para indução de embriogênese somática em região do meristema apical de plantas de pupunha mantidas em casa-de-vegetação. O efeito de três fontes de carbono: sacarose, glicose e manitol na indução de embriogênese somática foi avaliado. Embriões somáticos foram observados após a indução apenas nos meios contendo sacarose ou glicose em igual proporção.Effect of carbon source on somatic embryogenesis of Bactris gasipaesThin cell layer of meristematic region was successfully used to induce somatic embryogenesis in greenhouse-grown plants of pejibaye. The effects of three sources of carbohydrates, sucrose, glucose and mannitol on induction of somatic embryogenic calli were evaluated. Somatic embryos were observed on media containing either sucrose or glucose.Index terms: Thin cell layer, Glucose, Sucrose

Cytoplasmic segregation in onion root tip cells and formation of vacuoles

Onion root tips were studied both with transmission and scanning electron microscope. The cells in the meristematic region of initials were found to be little vacuolated. At early stages of cell differentiation areas free of ribosomes are segregated in the cytoplasm. No (or only incomplete) membranes delimiting such areas could be distinguished in most cases. Seemingly, the membraneous structures may form later or simultaneously with the progress of breakdown of biostructure of the cytoplasm in the segregated area. The microscopic image of cytoplasm in the segregated areas (and even of the vacuolar sap at early stages of vacuole formation) resembles the matrix of cytoplasm populated with ribosomes. The cytoplasm in the whole central area is segregated at early stages of differentiation of root cap cells. The process of autophagic vacuoles formation in which the preexisting endomembranes seemingly are involved is described. It is proposed that such vacuoles may form after separation of two unit membranes of a cisternae surrounding a portion of the cytoplasm or an organelle, followed by independent growth of an outer unit membrane.

Radioisotopic studies of DNA biosynthesis in relation to growth of Zea mays roots

Root growth consists of two basic processes, cell division and cell elongation. An integral part of the first process is the synthesis of deoxyribonucleic acid (DNA). DNA biosynthesis was studied in primary roots of <em>Zea mays</em> through incorporation of ³H-thymidine by autoradiography and liquid scintillation spectrometry. DNA synthesis was restricted to the meristematic region of the primary root. The curve representing this process was bell-shaped with a peak at 1.5 mm from the tip. Up to 3 mm distance from the tip, the root was growing both by cell division and cell elongation. This was also the region of DNA synthesis. The root region between 3 to 9 mm from the tip. was growing only by cell elongation. The relative elemental rate of elongation had a maximum at 3.5 mm from the tip, or shortly after cessation of DNA synthesis and cell division. Cells stopped elongating at 9 mm distance from the tip.

Pericarp development in the macaw palm Acrocomia aculeata (Arecaceae)

The anatomy of the pericarp of the macaw palm (Acrocomia aculeata) was followed during development. Ovaries of flowers collected at anthesis of the bracts as well as pericarps were evaluated at different development phases using traditional plant anatomy techniques. The ovary wall has two meristematic regions, one adjacent to the external epidermis and the other surrounding the seminal cavity. The external meristematic region gives rise to the woody exocarp, and the internal meristematic region is responsible for thickening of the oily/fibrous mesocarp as well as the hard endocarp. Sclerification of the exocarp and endocarp occurs approximately 70 days after anthesis and defines the final fruit volume. Lignification of the exocarp cell layers is incomplete, lending porosity to the structure. Numerous canals develop in the mesocarp that are formed by the fusion of raphide-containing idioblasts. Lignification of the sclereids and their generally random arrangement confers impermeability and rigidity to the endocarp. In mature fruits, lipidic reserves are observed in parenchymatic cells of the mesocarp, and the germination pore in the endocarp is composed of parenchymatic cells.

Effect of triazophos on mitotic activity and chromosomal behavior in root meristems of Allium cepa L.

Effect of triazophos (an organophosphorous insecticide) on mitotic activity and chromosomal behavior in the meristematic region of root tip cells of Allium cepa L. was assessed. The insecticide showed mitotic depression and positive chromo-toxic effects. Abnormalities, such as stickiness, plasmolysed cells, equatorial plate shifting, polar shifting, irregular chromosome arrangement, precocious arms formation, bridge formation, C-metaphase, fragmentation of chromosomes, unequal cytokinesis, diagonal cytokinesis, delayed cytokinesis and formation of binucleated cells, were recorded in the chemically pretreated root meristem. Key-words: chromosomal and cellular abnormalities; cytotoxic effect; mitotic index; phase indices.DOI: 10.3126/botor.v6i0.2903 Botanica Orientalis - Journal of Plant Science (2009) 6: 4-7

ROLES OF PLANT GROWTH REGULATORS ON ADVENTITIOUS ROOTING OF SOME BANANA GENOTYPES (Musa sp.)

Some of Musa cultivars were used in this study: Cauman (AA), Giahuong (AAA), Su (AAB) and Hot (BB). Auxins (IAA, NAA, or 2,4-D at different concentrations) were used to induce adventitious rooting from explants containing a apical shoot and young leaves. Histological changes in the rooting were analysed under microscope. This process included following stages: activation of cell divisions, initiating of meristematic region, formation of root primordium, and root elongation. Roles of genotypes, plant growth regulators in this adventitious rooting were discussed.