Aluminum (Al) toxicity in plants is one of the primary constraints in crop production. Al³⁺, the most toxic form of Al, is released into soil under acidic conditions and causes extensive damage to plants, especially in the roots. In rice, Al tolerance requires the ASR5 gene, but the molecular function of ASR5 has remained unknown. Here, we perform genome-wide analyses to identify ASR5-dependent Al-responsive genes in rice. Based on ASR5_RNAi silencing in plants, a global transcriptome analysis identified a total of 961 genes that were responsive to Al treatment in wild-type rice roots. Of these genes, 909 did not respond to Al in the ASR5_RNAi plants, indicating a central role for ASR5 in Al-responsive gene expression. Under normal conditions, without Al treatment, the ASR5_RNAi plants expressed 1.756 genes differentially compared to the wild-type plants, and 446 of these genes responded to Al treatment in the wild-type plants. Chromatin immunoprecipitation followed by deep sequencing identified 104 putative target genes that were directly regulated by ASR5 binding to their promoters, including the STAR1 gene, which encodes an ABC transporter required for Al tolerance. Motif analysis of the binding peak sequences revealed the binding motif for ASR5, which was confirmed via in vitro DNA-binding assays using the STAR1 promoter. These results demonstrate that ASR5 acts as a key transcription factor that is essential for Al-responsive gene expression and Al tolerance in rice.

Glandular trichomes evolved three times independently in the genus. In two cases, these glandular trichomes are oil-secreting, suggesting that the corresponding flowers might be pollinated by oil-bees. Biogeographical patterns indicate expansions from Central America and the northern Andes to the subandean ranges between Chile and Argentina and to the extended area of the Paraná river basin. The distribution of oil-flower species across the phylogenetic trees suggests that oil-producing trichomes may have played a key role in the diversification of the genus, a hypothesis that requires future testing.

Iridaceae is one of the few families in which floral oils are produced and collected by pollinators as a resource. Perigonal nectaries and trichomal elaiophores are highly unusual within the tribe Sisyrinchieae. Both structures occur mainly on the staminal column, while they are usually distributed on the tepals in the other tribes of the subfamily Iridoideae. Sisyrinchieae is the largest tribe of Iridaceae present on the American continent, and the diversity observed may be related to the exceptional development of trichomal elaiophores within the genus Sisyrinchium, but knowledge concerning the other types of nuptial glandular structures within the tribe is still limited, preventing us from estimating their implication for species diversity. Structural observations and histochemical tests were performed to identify and characterize glandular structures and pollen rewards within the flowers of the genera Orthrosanthus, Sisyrinchium and Solenomelus. Perigonal nectaries were detected only in Solenomelus segethi, and trichomal elaiophores were characterized only within Sisyrinchium. All species showed large amounts of additional resources available for pollinators in the form of pollenkitt and polysaccharides present in the cytoplasm of the pollen grains. The results are discussed in a phylogenetic context, with regard to pollinators and floral rewards reported for the tribe Sisyrinchieae.

The polyploid species Herbertia lahue (Molina) Goldblatt is widespread in the grassland areas of southern America. In this study, genotypic and phenotypic variations among hexaploids and octoploids from H. lahue were assessed based on quantitative floral traits and ISSR markers. Additionally, gynoecium and breeding systems were analysed through anatomical analysis and hand-pollination experiments. Cytotypes are self-compatible, and the anatomy of the embryo sac remains similar in hexaploids and octoploids. AMOVA indicates that hexaploid populations are less genetically variable than octoploids (respectively 4 and 22 %, P \ 0.001), thus the largest source of genetic variation for H. lahue lies among populations (82 %, P \ 0.001), probably a combined effect of selfing, changes in population size, and local adaptation. Genetic variation between cytotypes was significant (16 %, P \ 0.001), though unclear segregation among cytotypes was discovered through PCoA. A Mantel test indicated no relationship between geographic and genetic distances (r = 0.04; P = 0.37), possibly as a result of the combined effect of the recurrent origin of polyploids, gene flow restricted by selfing, and poor capacity for seed dispersal. In terms of floral measurements, eight measures of perigonium, androecium, and gynoecium varied significantly between cytotypes, though no clear grouping was defined by PCA. Presumably, complex variation in floral characters across cytotypes may result in the absence of distinct grouping by PCA. The combined use of ISSR markers and morphological characters revealed a complex relationship between H. lahue cytotypes shaped by both intrinsic and extrinsic factors.

Morphological and structural features of flowers of Trichilia catigua A. Juss., T. elegans A. Juss. and T. pallida Sw. (Meliaceae) are presented here with the purpose to stimulate future reproductive and preservation studies of these brazilian native species. Anthesis occurred from April to August in T. catigua, January to May in T. pallida and September to January in T. elegans. Sepals and petals presented a papillose and pilose epidermis and a parenchymatous mesophyll. Male flowers presented pistillodes with abortive ovules and a staminal tube with tetrasporangiate anthers. Anther wall had a papilose epidermis, a fibrous endothecium, two middle layers and a secretory tapetum. Female flowers presented antherodes and bi - or tricarpellate syncarpous pistils. Ovary had a simple structure with anatropous, bitegmic ovules. Style was hollow or solid and the stigma was constituted by uni - or bicelullar trichomes. Strictly dioecious specimens were not found in the study area.
As características morfológicas e anatômicas das flores de Trichilia catigua A. Juss., T. elegans A. Juss. e T. pallida Sw. (Meliaceae) são descritas no presente trabalho, visando subsidiar futuros estudos sobre reprodução e preservação destas espécies nativas. A antese ocorreu de abril a agosto em T. catigua, de janeiro a maio em T. pallida e setembro a janeiro em T. elegans. As sépalas e pétalas apresentavam epiderme papilosa e pilosa e mesofilo parenquimático. As flores masculinas possuiam pistilódio com óvulos abortivos e tubo estaminal com número variável de anteras tetrasporangiadas, cuja parede apresentava epiderme papilosa, endotécio, duas camadas médias e tapete secretor. As flores femininas apresentavam anteródios e pistilo bi ou tricarpelar, com ovário de estrutura simples, estilete oco ou sólido com tecido transmissor central e estigma com pêlos uni ou bicelulares. Os óvulos eram anátropos e bitegumentados. Não foram encontrados no ambiente de estudo exemplares das espécies estritamente dióicos, sendo todos em maior ou menor grau monóicos

Non-diabetic individuals use hormones like insulin to improve muscle strength and performance. However, as insulin also leads the liver and the adipose tissue to an anabolic state, the purpose of this study was to investigate the effects of insulin on liver metabolism in trained non-diabetic Swiss mice. The mice were divided into four groups: sedentary treated with saline (SS) or insulin (SI) and trained treated with saline (TS) or insulin (TI). Training was made in a vertical stair, at 90% of the maximum load, three times per week. Insulin (0.3 U/kg body weight) or saline were given intraperitoneally five times per week. After eight weeks, tissue and blood were collected and in situ liver perfusion with glycerol+lactate or alanine+glutamine (4 mM each) was carried out. The trained animals increased their muscle strength (+100%) and decreased body weight gain (–11%), subcutaneous fat (–42%), mesenteric fat (–45%), and peritoneal adipocyte size (–33%) compared with the sedentary groups. Insulin prevented the adipose effects of training (TI). The gastrocnemius muscle had greater density of muscle fibers (+60%) and less connective tissue in the trained groups. Liver glycogen was increased by insulin (SI +40% and TI +117%), as well as liver basal glucose release (TI +40%). Lactate and pyruvate release were reduced to a half by training. The greater gluconeogenesis from alanine+glutamine induced by training (TS +50%) was reversed by insulin (TI). Insulin administration had no additional effect on muscle strength and reversed some of the lipolytic and gluconeogenic effects of the resistance training. Therefore, insulin administration does not complement training in improving liver glucose metabolism.

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