Hemicelluloses and associated compounds determine gall functional traits.

The intriguing questions concerning gall development refer to the processes of the remodelling of the host plant organ. Such processes involve the restructuring of cell walls and can be influenced by phenolics, indole-3-acetic acid (IAA) and reactive oxygen species (ROS). Alterations in cell walls demand the interference in the coupling of cellulose fibrils and hemicelluloses (xyloglucans) at specific stages of gall development. In addition to cell wall remodelling, hemicelluloses, such as the, xyloglucans and heteromannans can act as reserve carbohydrates, while xylans provide rigidity to the secondary cell walls. Developmental traits of the lenticular, fusiform and globoid galls on Inga ingoides (Fabaceae) were analysed using anatomical, cytometric, histochemical and immunocytochemical tools. Phenolics, IAA and ROS accumulated in similar gall tissue compartments, and may have influenced the restructuring of hemicelluloses and pectins. Contrary to expectations, cell wall flexibility regarding the dynamics of xyloglucans and cellulose fibrils does not relate to a temporal scale. The detection of xyloglucans in nutritive cell walls relate to carbohydrate nutritional resources to the galling insect, while xylans were associated to the lignified cell walls. Heteromanans were not detected, either in non-galled or galled tissues. The patterns of cell expansion during gall development relied on the relationship among phenolics, ROS and IAA with the hemicelluloses (xyloglucans and xylans) and cellulose fibrils. Although cell wall dynamics is specific to each gall morphotype in I. ingoides, the xyloglucans function as carbohydrate reserve to the gall inducers, which constitutes a functional trait common to the three morphotypes.

Unravelling the structure and function of the petal appendages in the tribe Schwenckieae (Solanaceae).

The tribe Schwenckieae (Solanaceae) is characterised by the presence of appendages on the corolla, a diagnostic trait for the group. These appendages constitute a median distal projection of the three-lobed petal and occur in the genera Melananthus and Schwenckia but are absent in Heteranthia. We investigated the micromorphology and anatomical structure of the appendages and lateral petal lobes of Schwenckia americana (two varieties), S. angustifolia, S. curviflora and S. novaveneciana, and Melananthus fasciculatus. We also performed histochemical tests to determine if the appendages are involved in the production of volatiles, acting as a fragrance secretory structure (osmophore). The appendages have a uniseriate epidermis, whose cells store phenolics and lipids. The parenchyma is starch-rich just prior to anthesis in all species studied. The sensory test and anatomical analyses identified scent-secreting tissues, not only in the appendages, but also in the lateral petal lobes, whose cells are papillose with a sculptured surface. The α-naphthol p-phenylenediamine (NADI) reaction detected volatile (essential oils) compounds in S. americana var. americana and S. americana var. angustifolia. We demonstrated the secretory tissues and the production of lipids in the corolla appendages of Schwenckia and Melananthus, which indicate their osmogenic function and probable scent emission to attract pollinators.

Enzyme-mediated metabolism in nutritive tissues of galls induced by Ditylenchus gallaeformans (Nematoda: Anguinidae).

The galls induced by Ditylenchus gallaeformans (Nematoda) on leaves of Miconia albicans have unique features when compared to other galls. The nematode colonies are surrounded by nutritive tissues with promeristematic cells, capable of originating new emergences facing the larval chamber, and providing indeterminate growth to these galls. Considering enzyme activity as essential for the translocation of energetic molecules from the common storage tissue (CST) to the typical nutritive tissue (TNT), and the major occurrence of carbohydrates in nematode galls, it was expected that hormones would mediate sink strength relationships by activating enzymes in indeterminate growth regions of the galls. Histochemical, immunocytochemical and quantitative analyses were made in order to demonstrate sites of enzyme activity and hormones, and comparative levels of total soluble sugars, water soluble polysaccharides and starch. The source-sink status, via carbohydrate metabolism, is controlled by the major accumulation of cytokinins in totipotent nutritive cells and new emergences. Thus, reducing sugars, such as glucose and fructose, accumulate in the TNT, where they supply the energy for successive cycles of cell division and for nematode feeding. The histochemical detection of phosphorylase and invertase activities indicates the occurrence of starch catabolism and sucrose transformation into reducing sugars, respectively, in the establishment of a gradient from the CST towards the TNT. Reducing sugars in the TNT are important for the production of new cell walls during the indeterminate growth of the galls, which have increased levels of water-soluble polysaccharides that corroborate such a hypothesis. Functional relationship between plant hormone accumulation, carbohydrate metabolism and cell differentiation in D. gallaeformans-induced galls is attested, providing new insights on cell development and plant metabolism.

Anatomical and phenological implications of the relationship between Schinus polygama (Cav.) (Cabrera) and the galling insect Calophya rubra (Blanchard).

The success of galling insects could be determined by synchronisation with host plant phenology and climate conditions, ensuring suitable oviposition sites for gall induction and food resources for their survival. The anatomical, histochemical and phenological synchronisation strategies between Calophya rubra (Blanchard) (Hemiptera: Psylloidea) and its host, the evergreen plant Schinus polygama (Cav.) (Cabrera) (Anacardiaceae), in the Mediterranean climate of southern Chile was evaluated and compared to that of the congeneric C. cf. duvauae (Scott) from Brazil and closely related host plant S. engleri in a subtropical climate. Anatomical, histometric, histochemical and vegetative phenology studies of the stem and galls were conducted from June 2015 to December 2016. Based on the anatomical, histometric and histochemical analysis, the conical stem gall traits imply gains over the non-galled stem toward the galling insect survival, but the maintenance of phellem, secretory ducts and pith indicate conservative developmental traits that cannot be manipulated by C. rubra. Our results indicate that the conditions of the Mediterranean climate zone limit C. rubra immature activity during unfavourable periods, probably determining a diapause period and a univoltine life cycle, which are peculiarities of the S. polygama- C. rubra system. The synchronisation between development and seasonality confers peculiarities to the S. polygama- C. rubra system in the Mediterranean climate zone.

Pectin and cellulose cell wall composition enables different strategies to leaf water uptake in plants from tropical fog mountain.

Leaf water uptake (LWU) has been observed in plants of different ecosystems and this process is distinct among different species. Four plant species from the Brazilian fog mountain fields were evaluated in order to detect if leaf water uptake capacity is related to the cell wall composition of leaf epidermis. LWU measurements and their relation to anatomical and biochemical traits were analyzed. Cell wall composition was verified through immunocytochemistry using monoclonal antibodies recognizing pectin compounds, and histochemistry with calcofluor white to track cellulose. Differences in LWU among the four species were clearly revealed. Two species presented higher maximum leaf water content and the lowest values of water absorption speed. The other two species presented opposite behavior, namely, low leaf water uptake and the highest values of water absorption speed. The anatomical traits associated with the cell wall composition corroborated the data on the different LWU strategies. The species with abundant detection of cellulose in their epidermal cell walls absorbed more water, but more slowly, while those with abundant detection of pectins absorbed water at a higher speed. These results indicate that cell wall composition regarding pectin and cellulose are significant for water uptake by the leaf epidermis. Pectin provides greater porosity and absorption speed, while cellulose provides greater hydrophilicity and greater water uptake capacity. Current data indicate that the composition of epidermal cell walls is a relevant trait for leaf water uptake.

Manipulation of host plant cells and tissues by gall-inducing insects and adaptive strategies used by different feeding guilds.

Biologists who study insect-induced plant galls are faced with the overwhelming diversity of plant forms and insect species. A challenge is to find common themes amidst this diversity. We discuss common themes that have emerged from our cytological and histochemical studies of diverse neotropical insect-induced galls. Gall initiation begins with recognition of reactive plant tissues by gall inducers, with subsequent feeding and/or oviposition triggering a cascade of events. Besides, to induce the gall structure insects have to synchronize their life cycle with plant host phenology. We predict that reactive oxygen species (ROS) play a role in gall induction, development and histochemical gradient formation. Controlled levels of ROS mediate the accumulation of (poly)phenols, and phytohormones (such as auxin) at gall sites, which contributes to the new cell developmental pathways and biochemical alterations that lead to gall formation. The classical idea of an insect-induced gall is a chamber lined with a nutritive tissue that is occupied by an insect that directly harvests nutrients from nutritive cells via its mouthparts, which function mechanically and/or as a delivery system for salivary secretions. By studying diverse gall-inducing insects we have discovered that insects with needle-like sucking mouthparts may also induce a nutritive tissue, whose nutrients are indirectly harvested as the gall-inducing insects feeds on adjacent vascular tissues. Activity of carbohydrate-related enzymes across diverse galls corroborates this hypothesis. Our research points to the importance of cytological and histochemical studies for elucidating mechanisms of induced susceptibility and induced resistance.

Phenotypic plasticity and similarity among gall morphotypes on a superhost, Baccharis reticularia (Asteraceae).

Understanding factors that modulate plant development is still a challenging task in plant biology. Although research has highlighted the role of abiotic and biotic factors in determining final plant structure, we know little of how these factors combine to produce specific developmental patterns. Here, we studied patterns of cell and tissue organisation in galled and non-galled organs of Baccharis reticularia, a Neotropical shrub that hosts over ten species of galling insects. We employed qualitative and quantitative approaches to understand patterns of growth and differentiation in its four most abundant gall morphotypes. We compared two leaf galls induced by sap-sucking Hemiptera and stem galls induced by a Lepidopteran and a Dipteran, Cecidomyiidae. The hypotheses tested were: (i) the more complex the galls, the more distinct they are from their non-galled host; (ii) galls induced on less plastic host organs, e.g. stems, develop under more morphogenetic constraints and, therefore, should be more similar among themselves than galls induced on more plastic organs. We also evaluated the plant sex preference of gall-inducing insects for oviposition. Simple galls were qualitative and quantitatively more similar to non-galled organs than complex galls, thereby supporting the first hypothesis. Unexpectedly, stem galls had more similarities between them than to their host organ, hence only partially supporting the second hypothesis. Similarity among stem galls may be caused by the restrictive pattern of host stems. The opposite trend was observed for host leaves, which generate either similar or distinct gall morphotypes due to their higher phenotypic plasticity. The Relative Distance of Plasticity Index for non-galled stems and stem galls ranged from 0.02 to 0.42. Our results strongly suggest that both tissue plasticity and gall inducer identity interact to determine plant developmental patterns, and therefore, final gall structure.

Cytological cycles and fates in Psidium myrtoides are altered towards new cell metabolism and functionalities by the galling activity of Nothotrioza myrtoidis.

The morphogenesis of galls occurs by the redifferentiation of cells that assume new functions in the modified host plant organs. The redifferentiated cells in the galls of Nothotrioza myrtoidis on Psidium myrtoides have low complexity metabolism and are photosynthesis-deficient. These galls were studied in search for evidences of the establishment of new cell cycles and fates and cytological gradients that corroborate their metabolic profile. Young and mature leaves of P. myrtoides and leaf galls induced by N. myrtoidis at different developmental stages were collected along 24 months and analyzed under light and transmission electron microscopy. The leaves of P. myrtoides are long-lasting and did not senesce within the analyzed period, while the galls have a shorter cycle, and senesce within 1 year. A homogenous parenchyma is established by a "standby-redifferentiation" of the chlorophyllous tissues, and sclerenchyma cells redifferentiate from parenchyma cells in the outer cortex of the mature galls. The lack of organelles, the underdeveloped lamellation of chloroplasts, and the occurrence of few plastoglobules are related to the photosynthetic deficiency of the galls. No cytological gradients were observed, but the organelle-rich cells of the vascular and perivascular parenchymas are similar to those of the nutritive tissues of galls induced by other insect taxa. These cells nearest to the feeding sites of N. myrtoidis present higher metabolism and well-developed apparatus for the prevention of oxidative stress. The features herein described corroborate the low metabolic profile of the galls as the cell cycles and fates of P. myrtoides are manipulated for completely new functionalities.

Illustrated and annotated checklist of Brazilian gall morphotypes.

The analysis on nine inventories on the richness and diversity of galling herbivores in Brazil accounted for 806 gall systems occurring in 443 host-plant species from 74 plant families. This checklist of the Brazilian gall morphotypes proposes seven standardized morphotypes and five additional shapes that group the majority of the three-dimensional shapes reported in literature. Criteria are proposed to standardize the terminology, and a critical analysis is provided aiming to avoid possible inconsistencies in order to generate easily comparable data in future inventories. The morphotypes are herein catalogued in alphabetical order, accompanied by a conceptual definition, an illustration, and examples that best represent the shape. It is proposed that the inventories should present at least the (1) host-plant species, (2) galling herbivore species or its identification to the lowest possible taxonomic level, (3) host-plant galled organ and gall position, (4) gall morphotype, (5) gall color and registration of indumentum when present, (6) gall phenological and developmental data, (7) association with other trophic levels, and (8) additional information, such as dimension, and number of chamber(s).

Aluminium localization and toxicity symptoms related to root growth inhibition in rice (Oryza sativa L.) seedlings.

We correlated root growth inhibition with aluminium (Al(3+)) localization and toxicity symptoms in rice roots using seedlings of two genotypes (tolerant and sensitive) that were exposed to different AlCl(3) concentrations. Al(3+) localization was evaluated by hematoxylin in primary roots and by morin in cross-sections of the root tips. Neutral invertase enzyme activity and callose (1 -- 3, beta-D-glucan) accumulation were observed and compared with Al(3+) accumulation sites. Root growth was inhibited by Al(3+) in a concentration-specific manner and proportional to the increase of hematoxylin staining, being more pronounced in the sensitive genotype. Morin staining showed the presence of Al(3+) deep within the roots of the sensitive genotype, indicating that the metal was able to penetrate beyond the first few cell layers. In the tolerant genotype, Al(3+) penetration was restricted to the first two cell layers. Ruptures in exodermis and epidermis layers by lateral root protrusions in both genotypes allowed Al3+ to enter into the roots. More intense activity of invertase in roots of the tolerant genotype was also observed, which could be related to greater root growth of this cultivar when submitted to Al(3+) stress. Moreover, Al(3+)-induced callose accumulation was a late response occurring in the same areas where Al(3+) was present.

Description of the female, pupa and gall of Pisphondylia brasiliensis Couri and Maia, 1992 (Diptera: Cecidomyiidae, Schizomyiina) with new records.

The gall of Pisphondylia brasiliensis on Guapira opposita, its female and pupa are described and illustrated. The geographic distribution of this species is now widened to Minas Gerais and Rio Grande do Sul (Brazil). For the first time, a female of the genus is described.

Caracterização botânica e química de Rudgea viburnoides (Cham.) Benth., (Rubiaceae) / Morphological and chemical diagnosis of Rudgea viburnoides (Cham.) Benth., (Rubiaceae)

Congonha, congonha-de-bugre e bugre são nomes populares atribuídos a várias espécies medicinais, incluindo Rudgea viburnoides (Cham.) Benth. (Rubiaceae), cujas folhas são utilizadas na medicina popular como diuréticas, hipotensoras, antireumáticas e depurativas do sangue. Esta espécie vem sendo comercializada como porangaba e utilizada em regimes de emagrecimento, substituindo Cordia ecalyculata Vell. (Boraginaceae). Neste estudo, foram determinadas as características botânicas, fisico-químicas e químicas para R. viburnoides com o objetivo de auxiliar sua identificação taxonômica e o controle de qualidade de produtos preparados com esta planta. Uma amostra referência foi coletada e submetida à caracterização macroscópica, microscópica e organoléptica, determinação de cinzas totais e umidade, prospecção fitoquímica e determinação dos perfis cromatográficos em CCD. Amostras de R. viburnoides podem ser reconhecidas pela epiderme pilosa com marcantes estrias cuticulares, estômatos paracíticos, presença de idioblastos com ráfides no mesofilo e pela configuração em arco dos tecidos vasculares da nervura de primeira ordem, caracteres ausentes em C. ecalyculata. A presença de cistólitos e canais mucilaginosos na medula diferem prontamente C. ecalyculata de R. viburnoides. A análise por CCD evidenciou a presença de flavonóides e saponinas. Amostras adquiridas no comércio e submetidas aos mesmos ensaios permitiram validar os métodos propostos e confirmaram a ampla comercialização de R. viburnoides em Minas Gerais.

Congonha, congonha-de-bugre and bugre are popular names for several medicinal plant species, including Rudgea viburnoides (Cham.) Benth. (Rubiaceae), whose leaves are widely used in popular medicine as diuretic, hypotensive, antirheumatic, and blood depurative. This species has been commercialized as porangaba, and used for diet purposes in substitution of Cordia ecalyculata Vell. (Boraginaceae). This study determines botanical, physico-chemical and chemical characteristics of R. viburnoides with the objective of providing tools for its taxonomical identification and the quality control of derived products. A reference sample was collected and submitted to macroscopical, microscopical and organoleptical characterization, total ash and water content, phytochemical screening, and TLC profile determination. Samples of Rudgea viburnoides can be easily distinguished from those of Cordia ecalyculata by the pilose epidermis with paracytic stomata, outstanding cuticularized striation, the presence of cristalliferous idioblasts, and by the arc pattern of the midvein vascular tissues. Furthermore, C. ecalyculata presents cystoliths and medullary mucilaginous channels differing from R. viburnoides. TLC analysis demostrated the presence of flavonoids and saponins. Commercially acquired samples submitted to the same assays have therefore validated the proposed methods, and confirmed the wide commercialization of R. viburnoides in the state of Minas Gerais, Brazil.