Embryogenesis in flowering plants: Recent approaches and prospects

The overall architectural pattern of the mature plant is established during embryogenesis. Very little is known about the molecular processes that underlie embryo morphogenesis. Last decade has, nevertheless, seen a burst of information on the subject. The synchronous somatic embryogenesis system of carrot is largely being used as the experimental system. Information on the molecular regulation of embryogenesis obtained with carrot somatic embryos as well as observations on sandalwood embryogenic system developed in our laboratory are summarized in this review. The basic experimental strategy of molecular analysis mostly relied on a comparison between genes and proteins being expressed in embryogenic and non-embryogenic cells as well as in the different stages of embryogenesis. Events such as expression of totipotency of cells and establishment of polarity which are so critical for embryo development have been characterized using the strategy. Several genes have been identified and cloned from the carrot system. These include sequences that encode certain extracellular proteins (EPs) that influence cell proliferation and embryogenesis in specific ways and sequences of the abscisic acid (ABA) inducible late embryogenesis abundant (LEA) proteins which are most abundant and differentially expressed mRNAs in somatic embryos. That LEAs are expressed in the somatic embryos of a tree flora also is evidenced from studies on sandalwood. Several undescribed or novel sequences that are enhanced in embryos were identified. A sequence of this nature exists in sandalwood embryos was demonstrated using aCuscuta haustorial (organ-specific) cDNA probe. Somatic embryogenesis systems have been used to assess the expression of genes isolated from non-embryogenic tissues. Particular attention has been focused on both cell cycle and histone genes     

Embryo Transformation, A Practical Approach for Realizing Transgenic Plants of Safflower (Carthamus tinctorius L.)

A gene transfer system that ensured recovery of whole planttransformants was developed for safflower (Carthamus tinctoriusL.). Embryo axes of germinating seeds with one of the cotyledonsremoved were pricked with a sterile sewing needle at the cotyledonarynode and infected by gentle agitation for 10 min in a suspensionofAgrobacterium tumefaciens . Following a 24 h co-cultivationand decontamination with cefotaxime for 1 h, they were placedon soilrite moistened with water to allow germination to progress.Later, the seedlings were transferred to soil in pots wherethey grew into normal healthy plants in the greenhouse. Thehistochemical assay of an uid A gene that expresses only inplant tissues and PCR amplification of uid A and npt II markergenes were used for early determination of putative transformants,whereas Southern analysis of T₀and T₁plant DNA was used to confirmintegration of the transgenes. The combined results indicatedthat the frequency of transformation was 5.3% in safflower ‘A-1’and 1.3% in ‘A-300’. Four T₀plants of ‘A-1’yielded transformed T₁progeny. The strategy, in principle, shouldbe applicable to all cultivars and genotypes of safflower whichare susceptible to Agrobacterium tumefaciens infection. Thusfar, this is the only procedure available for safflower thatcould successfully be used to generate whole plant transformants.Copyright 2000 Annals of Botany Company Safflower (Carthamus tinctorius L.), transformation, non-tissue culture method, embryo axes,Agrobacterium , transgene expression     

Brachystelma annamacharyae sp. nov. (Apocynaceae) from the Seshachalam hills of Andhra Pradesh (India)

Brachystelma annamacharyae K. Prasad, Prasanna, Meve, Sankara Rao & T. Thulasaiah, a new species from the Sanipaya beat in the Seshachalam hills in Andhra Pradesh (India) is described and illustrated. The new species shares the long filiform pedicels, reflexed corolla lobes and an exposed corona with its most closely allied species, B. swarupa from Kerala and B. ciliatum from Karnataka and Andhra Pradesh, but differs from these by generally dwarfed and completely glabrous vegetative parts and uniflowered inflorescences, therby resembling certain South African species of the genus.     

Phytochemical constituents of cultured cells of Eucalyptus tereticornis SM

Callus induced from shoot explants of Eucalyptus tereticornis was maintained for eight months on a defined MS medium. The lipid composition of the callus of E. tereticornis were -sitosterol, stigmasterol and cholesterol. In addition, we report the presence of a flavanoidal glycoside, aglycon identified as Kaempferol. Further, the presence of 2,3-dihydroxybenzaldehyde and 3,4-dihydroxyphenyl acetic acid was established from the methanol fraction.List of Abbreviations 2,4-D 2,4-Dichlorophenoxyacetic acid - Kn Kinetin - NAA 1-Naphthaleneacetic acid - IAA Indole-3-acetic acid - BA 6-Benzylaminopurine     

Declining Wild Mushroom Recognition and Usage in Burkina Faso

Declining Wild Mushroom Recognition and Usage in Burkina Faso. Ethnomycological investigation was carried out in Burkina Faso, West Africa, using standardized interviews focused on 40 representative mushroom species assembled in a traveling herbarium (photographs plus preserved specimens). A total of 540 informants from 18 localities representing three main ethnic groups—Mòosé, Bobo, and Gouin—were interviewed, though the bulk of those interviewed were Mòosé (or Mossi) from the more populous central region of the country. Among the study species, as many as 24 were considered edible by the different ethnic groups; a few medicinal uses also were noted. The edibility of a common Chlorophyllum species is confirmed for the three ethnic groups. Mushroom nomenclature is not well developed in any of the three groups as evidenced by the fact that many mushrooms, including some common edible species, do not appear to have specific local names, but are instead simply referred to by a general term for “mushroom.” Preliminary observations about inter–ethnic variation in recognition, naming, and appreciation of mushrooms are noted. Older people recognized many more mushroom species than did younger people, and women appeared to be slightly more knowledgeable about mushrooms than men. The most important finding is that the gathering and consumption of wild edible mushrooms seems to be dying out in Burkina Faso, especially in the central part of the country, apparently because of declining mushroom populations resulting from disappearing forest habitats. NOTE TO VENDOR: In place of the corresponding author, send proof to this paper’s editor, David Aroro, maxfun @cruzio.com     

Efficacy,prey stage preference and optimum predator–prey ratio of the predatory mite,Neoseiulus longispinosus Evans (Acari: Phytoseiidae) to control the red spider mite,Oligonychus coffeae Nietner (Acari: Tetranychidae) infesting tea

The predatory mite, N. longispinosus preys up on red spider mite, O. coffeae infesting tea in south India. An attempt has been made to determine the predatory potential, prey stage preference and optimum predator–prey ratio of N. longispinosus under laboratory and green house conditions. When 50 adult female O. coffeae were given, the number of adults reduced by eight days along with an increase in the number of predators. The larvae hatched from the eggs laid by O. coffeae were fed by predatory mite. N. longispinosus preyed up on all life stages with a preference to larvae and nymphs of red spider mite. Predator–prey ratios of 1:33 and 1:50 were effective in lab, and 1:25 was found to be effective in green house. These results revealed that N. longispinosus could be used as a successful biocontrol candidate of O. coffeae in tea through augmentation or mass rearing and field release.     

Novel approaches on identification of conserved miRNAs for broad-spectrum Potyvirus control measures

Molecular Biology Reports - Potyviridae comprises more than 200 ssRNA viruses, many of which have a broad host range and geographical distributions. Potyvirids (members of Potyviridae) infect...