Karyotype analysis of Solanum torvum Sw. - an ethnobotanical Solanaceous species of Tripura, North East India

Solanum torvum Sw. is a wild Solanaceous plant species, commonly used by the indigenous people of Tripura. Cytological study of the species was carried out to determine the somatic chromosome number and to construct the karyotype formula. The detailed karyomorphological analysis revealed 2n=24 somatic chromosomes having haploid number n=12. The size of chromosomal complement was found to range from 2.14±0.21 to 4.02±0.26 µm with a pair of chromosomes bearing secondary constrictions. Strictly median primary constriction was recorded in two pairs of chromosomes. In general, karyotype formula was found to be A2B4C18. The detailed karyotype analysis revealed that chromosomes are generally small in size and fall under the Stebbins category of “2A” indicating symmetrical nature of the karyotype. The present study could be utilised in understanding the cytogenetic nature of the species and for future crop improvement programme.

Selection of Macrolophus melanotoma between its main non-crop host plant (Dittrichia viscosa) and eggplant, pepper and tomato, in choice experiments

The host plant selection of the predator Macrolophus melanotoma (Costa) (=M. caliginosus Wagner) (Hemiptera: Miridae) was studied between: i) its major non-crop host plant, Dittrichia viscosa L. (W. Greuter) (Asteraceae) and the solanaceous plants eggplant, pepper and tomato, and ii) between eggplant, pepper and tomato, in choice experiments. The experiments were performed in cages where two potted plants without prey were placed. In each replicate, an adult predator was released in the centre of the cage or on the solanaceous plant. The position of the released predator in each cage was recorded at intervals of 20min, 1, 2, and 24h after its introduction. The results showed that M. melanotoma had a high selection preference rate for its origin host plant (D. viscosa) irrespectively of the solanaceous plant that was present in the cage. The experiments investigating the relative preference of M. melanotoma when given access only to solanaceous plants revealed that it preferred eggplant at higher rates than pepper and tomato. These data indicate that M. melanotoma originating from D. viscosa patches might have a very low potential to colonize pepper or tomato crops in the open field. However, its potential to colonize eggplant crops should be further evaluated.

IMPACTOS NUTRICIONAIS E PRODUÇÃO DE PIMENTÃO SUBMETIDO À DEFICIÊNCIA HÍDRICA(I)

IMPACTOS NUTRICIONAIS E PRODUÇÃO DE PIMENTÃO SUBMETIDO À DEFICIÊNCIA HÍDRICA(I) GÉSSICA SILVA LIMA1, FERNANDO BROETTO2; ANTÔNIO DE PÁDUA SOUSA1; JOSELINA DE SOUZA CORREIA1 E ALEXSANDRO OLIVEIRA DA SILVA3. (I) Parte da dissertação de mestrado do primeiro autor.1Departamento de Engenharia Rural, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, Botucatu-SP, [email protected], [email protected] de Química, Instituto de Biociências, Universidade Estadual Paulista, Botucatu-SP, [email protected] de Engenharia Agrícola, Universidade Federal do Ceará, Fortaleza-CE, [email protected] 1 RESUMO O pimentão é uma solanácea de origem americana com grande consumo no Brasil. Com objetivo de estudar os efeitos da deficiência hídrica sobre a cultura do pimentão, conduziu-se experimento em ambiente protegido. Os tratamentos foram constituídos pelo teor de água no solo (100%, 85%, 70% e 55% da umidade na capacidade de campo) organizados em blocos casualizados com 6 blocos, sendo as unidades experimentais compostas por 16 plantas. Durante o experimento (aos 47, 62, 77 e 92 dias após o transplantio) foram avaliados os teores de macronutrientes (N, P, K, Ca, Mg e S) e micronutrientes (B, Cu, Fe, Mn e Zn) em cada fração vegetal além da matéria seca dessas frações. Na colheita, determinou-se o número, largura, diâmetro e comprimento dos frutos de cada planta. As variáveis foram submetidas ao teste de média de Tukey a 5% de probabilidade. O teor de água no solo interferiu de maneira significativa nas variáveis produtivas. Para o acúmulo de nutrientes na massa seca (folha+caule) os elementos com maior absorção seguiram a seguinte ordem: K>N>Ca>Mg>S>P e Fe>Mn>Zn>B>Cu. Palavras-chave: Manejo da Irrigação, Capsicum annuum L., demanda hídrica. LIMA, G. S.; BROETTO, F.; SOUSA, A. P.; CORREIA, J. S.; SILVA, A. O.NUTRITIONAL IMPACTS AND PRODUCTION OF SWEET PEPPER UNDER WATER DEFICIT 2 ABSTRACT The sweet pepper is a solanaceous plant of American origin with large consumption in Brazil. In order to study the effects of water stress on the sweet pepper crop, an experiment was conducted in greenhouse. The treatments consisted of soil water content (100%, 85%, 70% and 55% of moisture in the soil field capacity) in a randomized block design with 6 replicates where the experimental units consisted of 16 plants. During the experiment (47, 62, 77 and 92 days after planting) levels of macronutrients (N, P, K, Ca, Mg and S) and micronutrients (B, Cu, Fe, Mn and Zn) present in each plant fraction and the dry mass of plants for the accumulation of these determination were determined. At harvest the number, width and length of fruits from each plant were obtained. Variables were subjected to Tukey test at 5% probability. The water content in the soil interfered significantly with productive variables. To the accumulation of nutrients in the dry matter (leaf + stem) the elements with higher absorption are ordered as follows: K> N> Ca> Mg> S> P and Fe>Mn> Zn> B> Cu. Keywords: Management of irrigation, Capsicum annuum L., water demand.

RNA-seq Analysis of Solanesol Biosynthesis Genes in Nicotiana tabacum

Solanesol is a noncyclic terpene alcohol composed of nine isoprene units and it mainly accumulates in solanaceous plants, especially tobacco (Nicotiana tabacum L.). Here, RNA-seq analyses of tobacco leaves, stems, and roots were used to identify solanesol biosynthesis genes. Six 1-deoxy-d-xylulose 5-phosphate synthase, two 1-deoxy-d-xylulose 5-phosphate reductoisomerase, two 2-C-methyl-d-erythritol 4-phosphate cytidylyltransferase, four 4-diphosphocytidyl-2-C-methyl-d-erythritol kinase, two 2-C-methyl-d-erythritol 2,4-cyclodiphosphate synthase, four 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate synthase, two 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase, six isopentenyl diphosphate isomerase, and two solanesyl diphosphate synthase (SPS) genes were identified to be involved in solanesol biosynthesis. Furthermore, the two N. tabacum SPS (NtSPS1 and NtSPS2), which had two conserved aspartate-rich DDxxD domains, were highly homologous with SPS enzymes from other solanaceous plant species. In addition, the solanesol contents of three organs, and leaves from four growing stages, corresponded with the distribution of chlorophyll. Our findings provide a comprehensive evaluation of the correlation between the expression of different biosynthetic genes and the accumulation of solanesol in tobacco.

NaD1 forms oligomeric complexes with phosphatidylinositol to lyse cell membranes

Cationic antimicrobial peptides (CAPs) are innate defense molecules produced by essentially all living species and represent a rich source of novel therapeutic molecules for the treatment of human diseases including cancer. Although several CAPs (mainly from amphibians and vertebrates) have been shown to exhibit direct toxicity against tumor cells, the underlying molecular mechanisms are not well understood. Nicotiana alata (ornamental tobacco) defensin 1, NaD1, is a Class II solanaceous plant defensin in the CAP family that exhibits antifungal activities. We have identified NaD1 as a potent molecule in killing mammalian tumour cells. Microscopy analyses have revealed that NaD1 induces cytolysis of tumor cells via the formation of large plasma membrane blebs. NaD1 was demonstrated to bind directly to phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2 or PIP2) resulting in disruption of cytoskeleton-membrane interactions and subsequent plasma membrane blebbing. To define the molecular basis of the interaction between NaD1 and PIP2, we determined the crystal structure of a NaD1:PIP2 complex. Strikingly, NaD1 forms a unique arch-shaped oligomer comprised of seven NaD1 dimers and 14 PIP2. The structure of the protein:lipid complex indicates that the presence of PIP2 is critical for oligomerisation of NaD1. Formation of NaD1:PIP2 oligomers was further confirmed by protein-protein crosslinking and transmission electron microscopy. Based on these data we propose that NaD1 is an innate pattern recognition molecule for PIP2 and forms a unique protein-lipid oligomeric complex that mediates permeabilisation of both microbes and tumour cells.