Brassinosteroids (BRs) are plant steroid hormones with structural similarity to mammalian sex steroids and ecdysteroids from insects. The BRs are synthesized from sterols and are essential regulators of cell division, cell elongation and cell differentiation. In this work we show that voriconazole, an antifungal therapeutic drug used in human and veterinary medicine, severely impairs plant growth by inhibiting sterol-14α-demethylation and thereby interfering with BR production. The plant growth regulatory properties of voriconazole and related triazoles were identified in a screen for compounds with the ability to alter BR homeostasis. Voriconazole suppressed growth of the model plant Arabidopsis thaliana and of a wide range of both monocotyledonous and dicotyledonous plants. We uncover that voriconazole toxicity in plants is a result of a deficiency in BRs that stems from an inhibition of the cytochrome P450 CYP51, which catalyzes a step of BR-dependent sterol biosynthesis. Interestingly, we found that the woodland strawberry Fragaria vesca, a member of the Rosaceae, is naturally voriconazole resistant and that this resistance is conferred by the specific CYP51 variant of F. vesca. The potential of voriconazole as a novel tool for plant research is discussed.

No abstract

The influence of different factors on microspore embryogenesis in Chinese cabbage (B. rapa ssp. chinensis) was studied. A genotype dependence for embryo formation was observed. The majority of embryos and plants were obtained from microspores isolated from flower buds (2-2.9 mm in length) and cultured in the NLN liquid medium with 13% sucrose (w/v) supplemented with 24 epibrassinolide and 1% activated charcoal. Embryos cultured on the 1/2 Murashige Skoog culture medium with 2% sucrose (w/v), 0.1 mg/L benzylaminopurine, and 3 g/L Phytagel stimulated the formation of secondary embryos that resulted in development of large number of doubled haploid plants.

Изучен процесс эмбриогенеза и отработаны элементы технологии получения удвоенных гаплоидов брокколи B. oleracea L. convar. botrytis (L.) Alef. var. italica Plenck в культуре микроспор in vitro. Было выявлено, что успешное развитие эмбриоидов происходит из микроспор, изолированных из бутонов длиной 4 и 5 мм, где преимущественно содержатся микроспоры-на поздней вакуолизированной, пыльца-на ранней двухклеточной стадии развития. Оптимальным режимом температурной обработки является обработка 32°С в течение первых 2-х суток после введения в культуру. Эмбриоиды были получены из пяти образцов брокколи: Arcadia F 1 , Everest, Green Valiant, Marathon F 1 , Furio. Наибольший выход эмбриоидов был получен у образца Green Valiant, где он составил до 140 эмбриоидов на чашку Петри, а наименьший-у Furio (до 3 эмбриоидов/чашку Петри). Первые деления в культуре микроспор у всех образцов наблюдали уже на 2-3 сутки культивирования. Дальнейшее развитие эмбриоидов шло по двум направлениямпутем прямого развития или с образованием суспензороподобных структур. Эмбриоиды, содержащие суспензор, развивались медленнее, чем бессуспензорные. Мы наблюдали образование эмбриоида не только на дистальном (по отношению к микроспоре) конце суспензороподобной структуры, но и образование цепочки из эмбриоидов, а также все возможные близнецовые комбинации эмбриоидов. Было показано, что метод получения эмбриоидов в культуре микроспор in vitro может быть использован не только для получения удвоенных гаплоидных растений, но и служить моделью для фундаментальных исследований по изучению этапов развития зиготических эмбриоидов и суспензоров.

Turnip is a biennial crop and, consequently, the creation of pure lines for breeding is a time-consuming process. The production of pure turnip lines using doubled haploids produced in isolated microspore culture has not been sufficiently developed. The aim of the present work was to determine some key factors inducing embryogenesis in the isolated microspore culture of turnip, as well as investigating the manners of embryo development. It was shown that the acidity of the medium is an important factor in embryo production; different optimal pH levels ranging from 6.2 to 6.6 corresponded to individual genotypes. Such factors as the cold treatment of buds and the addition of activated charcoal to the nutrient medium increased the responsiveness of all genotypes studied. The turnip variety ‘Ronde witte roodkop herfst’ demonstrated a genetic disorder in the development of microspores; namely, non-separation of some microspores from tetrads. In the in vitro culture, each of the daughter microspores developed on its own. This indicates the dependence of the possibility of embryogenesis in the turnip microspore culture on the genotype. Results suggest that the initiation of secondary embryogenesis in primary embryos leads to an increase in the proportion of doubled haploid plants.

Morphological diversity of haploid and doubled haploid forms of pepper produced in vitro using microspore/anther culture from F 2 Capsicum annuum L. (cultivar Zdorov'e) × C. chinense Jacq and BC 2 C. annuum L. (cultivar Zdorov'e) × C. chinense Jacq × Zdorov'e × Zdorov'e has been demonstrated. The pos sibility of application of this method for breeding has been pointed out.

No abstract

No abstract