ENHANCEMENT OF ADVENTITIOUS SHOOT REGENERATION IN SESAME (SESAMUM INDICUM L.) CULTIVAR PROMO KY USING ETHYLENE INHIBITORS

Ethylene produced by tissue, callus and plantlets in closed vessels may lead to abnormal plantlet growth and branching in vitro. Silver nitrate (AgNO3) and Cobalt chloride (CoCl2) are known as ethylene inhibitors. Therefore, the objective of this study was to evaluate the in vitro regeneration capacity of sesame cultivar Promo KY when exposed to culture media containing ethylene inhibitors. A protocol is presented for direct adventitious shoot organogenesis and complete plant regeneration. MS medium enriched with 1.0 mg/L Benzyl adenine (BA) induced adventitious shoot in axenic seedling-derived shoot tips. Addition of ethylene inhibitors AgNO3 (0.5- 5.0 mg/L) enhanced number of shoots from 2.7 to 3.7 shoot/explant as well as shoot length from 1.3 to 2.9 cm . In the case of a medium comprising of MS salts with Naphthyl-Acetic Acid (NAA) 0.05 mg/L, 63 root/explant was observed and root emergence occur after 25 days of culture. Addition of 3.0 mg/L AgNO3 improved root initiation to 79 root/explants and root emerged after 14 days. Addition of 5.0 mg/L CoCl2 increase the root length from 3.5 cm to 17 cm. These promotive effects may result from a reduction in ethylene concentration or inhibition of ethylene action. The results found in this study may be used to improve the multiple shoot and rooting efficiency of Sesame cultivars and possibly of other plant species

Effect of Growth Regulators on In Vitro Morphogenic Response of Boscia senegalensis (Pers.) Lam. Poir. Using Mature Zygotic Embryos Explants

The percent study describes the in vitro responses of mature zygotic embryos of Boscia senegalensis to different concentrations (0.0–5.0 mg/L) of 6-benzyladnine (BA), Thidiazuron (TDZ), α-Naphthalene acetic acid (NAA), and 2, 4-Dichlorophenoxyacetic acid (2, 4-D) supplemented on Murashige and Skoog medium (MS). The plant growth regulators (PGRs) were considerably affected the morphogenetic responses. BA produced adventitious shoots through two ways: direct organogenesis and auxiliary shoot formation. Both 2, 4-D and TDZ tend to produce callus, whereas NAA improve the development of embryos to seedlings. Maximum number of shoots/explant (14.8 ± 0.6) was obtained on MS medium supplemented with 3.0 mg/L BA. 67.0% of excised shoots were rooted either on 1/2 MS medium augmented with or without 0.25 mg/L IBA. The highest number of roots (1.2 ± 0.4) and root length (0.5 ± 0.2 cm) was produced on 0.25 mg/L IBA-containing medium. Regenerated plants were successfully acclimatized and transferred to the green house with 70% survival rate. All the plants appeared morphologically uniform with normal growth pattern. A rapid (30 days), efficient and without subculturing protocol for in vitro regeneration of B. senegalensis was developed

Dedifferentiation of leaf explants and antileukemia activity of an ethanolic extract of cell cultures of Moringa oleifera

The present study was aimed at developing an efficient protocol for callus induction from the leaves of Moringa oleifera and to investigate its crude extract antileukemia activity on leukemia cells. Several secondary metabolites are present in M. oleifera as the plant serves as reservoirs for various bioactive compounds. Callus cultures of M. oleifera were induced from leaf explants incubated on MS medium supplemented with different concentrations of 2,4-dichloro-phenoxyacetic acid (2,4-D). The crude extracts of the callus were evaluated in vitro for their activity against leukemia cells and hepatocarcinoma. Among the different concentrations, 2,4-D at 0.1 mg/l induced highest frequencies of callus growth index (7.8) when compared with other concentrations. Ethanolic extracts killed about 36% of abnormal cells among primary cells harvested from 3 patients with acute myeloid leukemia (AML) and hepatocarcinoma cells HpG2. These results provide an in vitro evidence and support the traditional use of M. oleifera leaf as a potent source of anticancer. However, more researches are needed at phytochemical and clinical levels to confirm the traditional use of this plant as anticancer.Keywords: Moinga olifera, callus culture, antileukemia, hepatocarcinom

Tuning Beforehand: A Foresight on RNA Interference (RNAi) and In Vitro-Derived dsRNAs to Enhance Crop Resilience to Biotic and Abiotic Stresses

Crop yield is severely affected by biotic and abiotic stresses. Plants adapt to these stresses mainly through gene expression reprogramming at the transcriptional and post-transcriptional levels. Recently, the exogenous application of double-stranded RNAs (dsRNAs) and RNA interference (RNAi) technology has emerged as a sustainable and publicly acceptable alternative to genetic transformation, hence, small RNAs (micro-RNAs and small interfering RNAs) have an important role in combating biotic and abiotic stresses in plants. RNAi limits the transcript level by either suppressing transcription (transcriptional gene silencing) or activating sequence-specific RNA degradation (post-transcriptional gene silencing). Using RNAi tools and their respective targets in abiotic stress responses in many crops is well documented. Many miRNAs families are reported in plant tolerance response or adaptation to drought, salinity, and temperature stresses. In biotic stress, the spray-induced gene silencing (SIGS) provides an intelligent method of using dsRNA as a trigger to silence target genes in pests and pathogens without producing side effects such as those caused by chemical pesticides. In this review, we focus on the potential of SIGS as the most recent application of RNAi in agriculture and point out the trends, challenges, and risks of production technologies. Additionally, we provide insights into the potential applications of exogenous RNAi against biotic stresses. We also review the current status of RNAi/miRNA tools and their respective targets on abiotic stress and the most common responsive miRNA families triggered by stress conditions in different crop species

Stay-Green Trait: A Prospective Approach for Yield Potential, and Drought and Heat Stress Adaptation in Globally Important Cereals

The yield losses in cereal crops because of abiotic stress and the expected huge losses from climate change indicate our urgent need for useful traits to achieve food security. The stay-green (SG) is a secondary trait that enables crop plants to maintain their green leaves and photosynthesis capacity for a longer time after anthesis, especially under drought and heat stress conditions. Thus, SG plants have longer grain-filling period and subsequently higher yield than non-SG. SG trait was recognized as a superior characteristic for commercially bred cereal selection to overcome the current yield stagnation in alliance with yield adaptability and stability. Breeding for functional SG has contributed in improving crop yields, particularly when it is combined with other useful traits. Thus, elucidating the molecular and physiological mechanisms associated with SG trait is maybe the key to defeating the stagnation in productivity associated with adaptation to environmental stress. This review discusses the recent advances in SG as a crucial trait for genetic improvement of the five major cereal crops, sorghum, wheat, rice, maize, and barley with particular emphasis on the physiological consequences of SG trait. Finally, we provided perspectives on future directions for SG research that addresses present and future global challenges

Active principle from Moringa oleifera Lam leaves effective against two leukemias and a hepatocarcinoma

Medicinal plants are important elements of indigenous medical system that have persisted in developing countries. Many of the pharmacological principles currently used as anticancer agents were first isolated from plants. However, some important anticancer agents are still extracted from plants because they cannot be synthesized chemically on a commercial scale due to their complex structures that often contain several chiral centers. The aim of this study was to test different extracts from the leaves of Moringa or drumstick tree (Moringa oleifera) for activity against leukemia and hepatocarcinoma cells in vitro. The extracts could kill majority (70 - 86%) of the abnormal cells among primary cells harvested from 10 patients with acute lymphoblastic leukemia (ALL) and 15 with acute myeloid leukemia (AML) as well as a culture of hepatocarcinoma cells (75% death), but most significantly by the hot water and ethanol extracts. In conclusion, M. oleifera may have potential for use as source of natural treatment for diseases such as cancer.Key words: Moringa oleifera, anti-cancer, acute lymphoblastic leukemia, acute myeloid leukemia, hepatocarcinoma

An RNAi-Based Control of Fusarium graminearum Infections Through Spraying of Long dsRNAs Involves a Plant Passage and Is Controlled by the Fungal Silencing Machinery.

Meeting the increasing food and energy demands of a growing population will require the development of ground-breaking strategies that promote sustainable plant production. Host-induced gene silencing has shown great potential for controlling pest and diseases in crop plants. However, while delivery of inhibitory noncoding double-stranded (ds)RNA by transgenic expression is a promising concept, it requires the generation of transgenic crop plants which may cause substantial delay for application strategies depending on the transformability and genetic stability of the crop plant species. Using the agronomically important barley-Fusarium graminearum pathosystem, we alternatively demonstrate that a spray application of a long noncoding dsRNA (791 nt CYP3-dsRNA), which targets the three fungal cytochrome P450 lanosterol C-14α-demethylases, required for biosynthesis of fungal ergosterol, inhibits fungal growth in the directly sprayed (local) as well as the non-sprayed (distal) parts of detached leaves. Unexpectedly, efficient spray-induced control of fungal infections in the distal tissue involved passage of CYP3-dsRNA via the plant vascular system and processing into small interfering (si)RNAs by fungal DICER-LIKE 1 (FgDCL-1) after uptake by the pathogen. We discuss important consequences of this new finding on future RNA-based disease control strategies. Given the ease of design, high specificity, and applicability to diverse pathogens, the use of target-specific dsRNA as an anti-fungal agent offers unprecedented potential as a new plant protection strategy

(A-E) The fungal silencing machinery is required for efficient SIGS in distal leaf parts.

<p><b>(A,B)</b> The fungal <i>dicer-like-1</i> mutant Fg-IFA65_Δdcl-1 heavily infected barley leaves despite a prior spray-treatment with <i>CYP3</i>-dsRNA. Photographs were taken at 6 dpi. <b>(C)</b> Gene-specific qPCR analysis of <i>CYP51A</i>, <i>CYP51B</i>, and <i>CYP51C</i> transcripts in the wild type Fg-IFA65 and the mutant Fg-IFA65_Δdcl-1 at 6 dpi in the distal, semi-systemic leaf areas. <b>(D)</b> Inhibition of <i>CYP51</i> gene expression upon <i>CYP3</i>-dsRNA treatment of axenically grown Fg-IFA65_- Bars represent mean values ±SDs of three independent sample collections. The reduction in <i>CYP51</i> expression in samples treated with <i>CYP3</i>-dsRNA compared with mock-treated controls was statistically significant (*P < 0.05, **P < 0.01; Student´s t test). <b>(E-G)</b> Profiling of <i>CYP3</i>-dsRNA-derived sRNAs in axenically grown Fg-IFA65. (E) Scaffold of the 791 nt long <i>CYP3</i>-dsRNA. The fragments of <i>CYP51</i> genes are indicated. (F,G) Total sRNAs were isolated from axenically-cultured Fg-IFA65. sRNA reads of fungal sRNAs from untreated (F) and <i>CYP3</i>-dsRNA-treated (G) fungal cultures are mapped to the sequence of <i>CYP3</i>-dsRNA.</p

(A-E) The fungal silencing machinery is required for efficient SIGS in distal leaf parts.

<p><b>(A,B)</b> The fungal <i>dicer-like-1</i> mutant Fg-IFA65_Δdcl-1 heavily infected barley leaves despite a prior spray-treatment with <i>CYP3</i>-dsRNA. Photographs were taken at 6 dpi. <b>(C)</b> Gene-specific qPCR analysis of <i>CYP51A</i>, <i>CYP51B</i>, and <i>CYP51C</i> transcripts in the wild type Fg-IFA65 and the mutant Fg-IFA65_Δdcl-1 at 6 dpi in the distal, semi-systemic leaf areas. <b>(D)</b> Inhibition of <i>CYP51</i> gene expression upon <i>CYP3</i>-dsRNA treatment of axenically grown Fg-IFA65_- Bars represent mean values ±SDs of three independent sample collections. The reduction in <i>CYP51</i> expression in samples treated with <i>CYP3</i>-dsRNA compared with mock-treated controls was statistically significant (*P < 0.05, **P < 0.01; Student´s t test). <b>(E-G)</b> Profiling of <i>CYP3</i>-dsRNA-derived sRNAs in axenically grown Fg-IFA65. (E) Scaffold of the 791 nt long <i>CYP3</i>-dsRNA. The fragments of <i>CYP51</i> genes are indicated. (F,G) Total sRNAs were isolated from axenically-cultured Fg-IFA65. sRNA reads of fungal sRNAs from untreated (F) and <i>CYP3</i>-dsRNA-treated (G) fungal cultures are mapped to the sequence of <i>CYP3</i>-dsRNA.</p