INDEPENDENT ORIGINATION OF FLORAL ZYGOMORPHY, A PREDICTED ADAPTIVE RESPONSE TO POLLINATORS: DEVELOPMENTAL AND GENETIC MECHANISMS

Observations of floral development indicate that floral organ initiation in pentapetalous flowers more commonly results in a medially positioned abaxial petal (MAB) than in a medially positioned adaxial petal (MAD), where the medial plane is defined by the stem and the bract during early floral development. It was proposed that the dominant MAB petal initiation might impose a developmental constraint that leads to the evolution of limited patterns of floral zygomorphy in Asteridae, a family in which the floral zygomorphy develops along the medial plane and results in a central ventral (CV) petal in mature flowers. Here, I investigate whether the pattern of floral organ initiation may limit patterns of floral zygomorphy to evolve in pentapetalous angiosperms. I analyzed floral diagrams representing 405 species in 330 genera of pentapetalous angiosperms to reconstruct the evolution of floral organ initiation and the evolution of developmental processes that give rise to floral zygomorphy on a phylogenetic framework. Results indicate that MAB petal initiation is the most common; it occupies 86.2% of diversity and represents the ancestral state of floral organ initiation in pentapetalous angiosperms. The MAD petal initiation evolved 28 times independently from the ancestral MAB petal initiation. Among the 34 independent originations of floral zygomorphy, 76.5% of these clades represent MAB petal initiation, among which only 47% of the clades result a CV petal in mature flowers. The discrepancy is explained by the existence of developmental processes that result in floral zygomorphy along oblique planes of floral symmetry in addition to along the medial plane. Findings suggest that although the early floral organ initiation plays a constraining role to the evolution of patterns of floral zygomorphy, the constraint diverges along phylogenetically distantly related groups that allow the independent originations of floral zygomorphy through distinct development processes in pentapetalous angiosperms. In additional study, the butterfly-like flowers of Schizanthus are adapted to pollination by bees, hummingbirds, and moths. I investigated the genetic basis of the zygomorphic corolla, for which development is key to the explosive pollen release mechanism found in the species of Schizanthus adapted to bee pollinators. I examined differential gene expression profiles across the zygomorphic corolla of Schizanthus pinnatus, a bee-pollinated species, by analyzing RNA transcriptome sequencing (RNA- seq). Data indicated that CYC2 is not expressed in the zygomorphic corolla of Sc. pinnatus, suggesting CYC2 is not involved in the development of floral zygomorphy in Schizanthus (Solanaceae). The data also indicated that a number of genes are differentially expressed across the corolla

Comparative analysis of plant immune receptor architectures uncovers host proteins likely targeted by pathogens.

BACKGROUND: Plants deploy immune receptors to detect pathogen-derived molecules and initiate defense responses. Intracellular plant immune receptors called nucleotide-binding leucine-rich repeat (NLR) proteins contain a central nucleotide-binding (NB) domain followed by a series of leucine-rich repeats (LRRs), and are key initiators of plant defense responses. However, recent studies demonstrated that NLRs with non-canonical domain architectures play an important role in plant immunity. These composite immune receptors are thought to arise from fusions between NLRs and additional domains that serve as "baits" for the pathogen-derived effector proteins, thus enabling pathogen recognition. Several names have been proposed to describe these proteins, including "integrated decoys" and "integrated sensors". We adopt and argue for "integrated domains" or NLR-IDs, which describes the product of the fusion without assigning a universal mode of action. RESULTS: We have scanned available plant genome sequences for the full spectrum of NLR-IDs to evaluate the diversity of integrations of potential sensor/decoy domains across flowering plants, including 19 crop species. We manually curated wheat and brassicas and experimentally validated a subset of NLR-IDs in wild and cultivated wheat varieties. We have examined NLR fusions that occur in multiple plant families and identified that some domains show re-occurring integration across lineages. Domains fused to NLRs overlap with previously identified pathogen targets confirming that they act as baits for the pathogen. While some of the integrated domains have been previously implicated in disease resistance, others provide new targets for engineering durable resistance to plant pathogens. CONCLUSIONS: We have built a robust reproducible pipeline for detecting variable domain architectures in plant immune receptors across species. We hypothesize that NLR-IDs that we revealed provide clues to the host proteins targeted by pathogens, and that this information can be deployed to discover new sources of disease resistance

Jumping plant-lice of the Paurocephalinae (Insecta, Hemiptera, Psylloidea): systematics and phylogeny

Much confusion exists with respect to the content and definition of the psyUid subfamily Paurocephalinae. Based on a cladistic analysis of 22 morphological characters (16 adult and 6 larval), the subfamily is redefined to comprise the following five valid genera: Aphorma (3 species), Camarotoscena (12 valid species, with 1 new synonymy), DiC/idophlebia (= Aconopsylla, Haplaphalara, Paraphalaroida, Sinuonemopsylla and Woldaia; 24 species), Paurocephala (52 species) and Syntomoza (= Anomoterga and Homalocephata; 7 species). The tribe Diclidophlebiini is synonymised with the subfamily Paurocephalinae. The seven new generic synonymies produce 25 new species combinations. A key to genera for adults and fifth instar larvae is presented. In their revised definitions the genera exhibit relatively restricted distributions and host ranges: Aphorma: Palaearctic, Oriental - Ranunculaceae; Camarotoscena: Palaearctic - Salicaceae; Diclidophtebia: pantropical - Tiliaceae, Malvaceae, Sterculiaceae, Melastomataceae, Rhamnaceae, Ulmaceae and Euphorbiaceae; Paurocephala: Old World tropics - Moraceae, Urticaceae. Ulmaceae (all Urticales), Malvaceae. Sterculiaceae (all Malvales) and Clusiaceae (rheales); Syntomoza: Oriental, Afrotropical, Palaearctic - Flacourtiaceae, Salicaceae. The following taxa which have been referred to the Paurocephalinae are transferred to other taxa: Atmetocranium to the Calophyidae and Primascena to the Aphalaroidinae; Pseudaphorma is symonymised with Aphatara, and P. astigma with A. polygoni; the position of Strophingia is confirmed in the Strophingiinae.peer-reviewe

Tree Species Composition and Forest Stratification along the Gradients in the Dry Deciduous Forests of Godavari Valley, Telangana, India

It is important to understand the tree species composition, abundance, species diversity and stratification in tropical dry deciduous forests that are under threat. A quadrat study was attempted in the dry deciduous forests along the ecological gradients in the Godavari Valley of northern Telangana, India. The study records the presence of 110 flowering plant taxa belonging to 82 genera and 37 families in 120 sampled plots, and there was enumeration of 15,192 individuals of ≥10 cm girth at breast height. Tectona grandis (teak) is the principal forest cover component in the region, which often formed pure stands in Adilabad and, to some extent, in Nizamabad districts. Further down to the Warangal district, teak was gradually replaced by Terminalia alata. Twenty tree species were found dominant at one place to the other, and the top 10 dominant taxa have shared nearly 41% of the total density of the forest cover. The tree relative density ranged from 0.007% to 20.84%. The values of Importance Value Index were between 0.245 (12 spp. including some exotics) and 32.6 (teak). These baseline data help to know the change detection along the gradients in the tropical forest ecosystem of a major river valley in the region and the drivers of change

Sobre la presencia de Abutilon arboreum (L. f.) Sweet (Malvaceae) en la flora valenciana

Se cita por primera vez en la Comunidad Valenciana la presencia de Abutilon arboreum (L. f.) Sweet (Malvaceae), localizada en los márgenes de la Autovía V-30 y próxima al cauce del río Turia, en la provincia de Valencia (España).Abutilon arboreum (L. f.) Sweet (Malvaceae) in the Valencian flora (Spain). A first reference on the presence of Abutilon arboreum (L. f.) Sweet (Malvaceae) in Valencia Community (Spain) is provided. This species has been located at the V-30, highway next to the Turia River in the Valencian province (Spain)

An Angiosperm species dataset reveals relationships between seed size and two-dimensional shape

Datasets containing information on seed size have been published and are currently available. Nevertheless, there is a lack in the literature of a dataset dedicated to seed shape. We present a preliminary version for a dataset on seed morphology based on a comparison of seed shape with geometric figures. Similarity of the outline of seed images with geometric models is considered as a basis to classify seeds according to the geometric figures they resemble (e.g., ellipse, oval, cardioid). This allows, first, the classification of plant species according to their geometric type of seed, and second, seed shape quantification. For each seed image, the percent of similarity of their outline with a geometric figure can be calculated as a J index. Similarity in absolute terms is considered only when the J index >90. This criterion is important to avoid ambiguity and increase discrimination. The dataset opens the possibility of studying the relationship between seed shape and other variables such as seed size, genome complexity, life form or adaptive responses