Control of Leaf Width by the APC/CTAD1-WL1-NAL1 Pathway in Rice

Leaf morphology is one of the most important features of the ideal plant architecture. However, the genetic and molecular mechanisms controlling leaf morphology in crops remain largely unknown, despite their central importance. Here we demonstrate that the APC/CTAD1-WL1-NAL1 pathway regulates leaf width in rice, and mutation of WL1 leads to width leaf variation. WL1 interacts with TAD1 and is degraded by APC/CTAD1, with the loss of TAD1 function resulting in narrow leaves. The WL1 protein directly binds to the regulatory region of NAL1 and recruits the corepressor TOPLESS-RELATED PROTEIN to inhibit NAL1 expression by down-regulating the level of histone acetylation of chromatin. Furthermore, biochemical and genetic analyses revealed that TAD1, WL1, and NAL1 function in a common pathway to control leaf width. Our study establishes an important framework for the APC/CTAD1-WL1-NAL1 pathway-mediated control of leaf width in rice and introduces novel perspectives for using this regulatory pathway for improving crop plant architecture.

Tricky Morphology: A New Species of Chamaecrista (Leguminosae) Shows Strong Morphological Convergence Among Not Closely Related Species Found in Similar Habitat

Abstract— Plants from Brazilian campos rupestres usually present morphological strategies that allow them to survive in extreme environments. However, in Chamaecrista (Leguminosae, Caesalpinioideae), one of the most diverse genera in the campos rupestres, needle-like leaflets are rare. Reviewing the species that present such leaf morphology, we describe Chamaecrista acicularis, a new species from the Canastra Range, in the southwestern region of the state of Minas Gerais, Brazil. Phylogenetic analyses revealed that C. acicularis is not closely related to other quite similar needle-like leafleted species and that this trait evolved convergently. We also present comments on the phylogenetic relationships of needle-like leafleted species as well as the evolution of the leaflet amplitude, and a detailed description of C. acicularis alongside illustrations, photos, geographical distribution, a key to the needle-like leafleted species and taxonomic notes on similar species. Additionally, we expand the description of Chamaecrista strictifolia and present an informal conservation status for all needle-like leafleted species.

Two New Species of Balanophora (Balanophoraceae) From South China

Abstract— Populations of Balanophora from southern China are often identified by local botanists as B. laxiflora based on their long cylindric male inflorescence, subsessile male flowers with slender rudimentary bracts, and subdiscoid synandria. In this study, we clarify the identity of seven such populations based on morphological characters and phylogenetic analysis using nuclear 18S and ITS ribosomal DNA sequences. We confirmed the occurrence of dioecious populations of B. yakushimensis and two previously unrecognized species, which we describe here as B. parajaponica and B. appressa. Phylogenetic analyses indicated that B. parajaponica, B. yakushimensis, B. appressa, B. laxiflora, and the agamospermic B. japonica, formed a well resolved clade, viz. the B. laxiflora clade. The four dioecious species, although highly similar in the morphology of male inflorescence and flowers, can be separated by leaf morphology and arrangement, ovary color, and arrangement of female flowers. The species limit of B. laxiflora, however, remains unresolved.

Comparative leaf morphology and anatomy on ten taxa of Calycanthaceae Lindl. (Laurales)

The comparative leaf morphology and anatomy of ten species of family Calycanthaceae have been studied. Leaf anatomy is very comparable to each other in cell shape and their arrangement. Collected leaves were preserved in FAA and alcohol series were applied for LM and SEM. The layer of epidermis is two in Idiospermum and one in rest of other genera. The structure of vascular bundle is V-shape in Sinocalycanthus and Calycanthus whereas U-shape in Idiospermum and Chimonanthus. The density of trichome is higher in Calycanthus than other genera. The presence of trichome, stomata, epidermal layer, density of trichome and stomata, and leaf surface are represented the distinction among the genera. The adaxial surface of Idiospermum and Sinocalycanthus are smooth whereas of Calycanthus and Chimonanthus are rough. The crystals are present in Calycanthus, Sinocalycanthus and Chimonanthus whereas absent in Idiospermum. The shape of the vascular bundle, density of trichome, epidermal layer, and crystals play important role in the phylogenetic relationship of Calycanthaceae.

Leaf morphology, wax composition, and residual (cuticular) transpiration of four poplar clones

Key message We identified two poplar clones of the same species as highly comparable, yet clones of two further species of the same genus to be distinctly different regarding multiple morphological and ecophysiological traits. Abstract Leaf morphology, wax composition, and residual (cuticular) transpiration of four poplar clones (two clones of the hybrid species P. × canescens, P. trichocarpa, and P. euphratica) were monitored from the beginning to end of the growing season 2020. A pronounced epicuticular wax coverage was found only with P. euphratica. As the most prominent substance classes of cuticular wax primary alcohols, alkanes and esters were identified with P. × canescens and P. trichocarpa, whereas esters and alkanes were completely lacking in P. euphratica. Wax amounts were slightly decreasing during the season and significantly lower wax amounts were found for newly formed leaves in summer compared to leaves of the same age formed in spring. Residual (cuticular) transpiration was about five to tenfold lower for P. × canescens compared with the two other poplar species. Interestingly, with three of the four investigated species, newly formed leaves in summer had lower wax coverages and lower rates of residual (cuticular) transpiration compared to leaves of exactly the same age formed in spring. Our findings were especially surprising with P. euphratica, representing the only one of the four investigated poplar species naturally growing in very dry and hot climates in Central Asia. Instead of developing very low rates of residual (cuticular) transpiration, it seems to be of major advantage for P. euphratica to develop a pronounced epicuticular wax bloom efficiently reflecting light.

Relevance of leaf morphology and biometrics: a study with species of Aphelandra R. Br. (Acanthaceae)

Morphological characteristics, as well as biometrics, govern the description of species. However, systematical comparative analyzes of these aspects between taxa are scarce. The aim of the work was to evaluate the relevance of these characteristics in species of Aphelandra. Leaves of A. longiflora, A. harleyi, A. espirito-santensis, A. nitida, A. sinclairiana and A. squarosa were collected and analyzed for morphologic patterns: phyllotaxis, texture, leaf blade form, symmetry, apex, base, margin, venation and coloring pattern; and for biometric parameters: total length, length and width of the leaf blade, length and diameter of the petiole. We calculated mean and standard deviations. Among the relevant morphological patterns are the shape of the blade, apex and base, and the biometric data showed differences. As conclusion, this analysis proposal proves to be an instrument of accuracy and detail for descriptions.

Petrocodon anoectochilus, a Remarkable New Species of Gesneriaceae from Guangxi and Guizhou, Southwest China

Petrocodon anoectochilus F. Wen & B. Pan, a new species of Gesneriaceae from Guangxi and Guizhou in southwestern China, is described and illustrated. Although the leaf morphology of this new species looks similar to that of P. coriaceifolius (Y. G. Wei) Y. G. Wei & Mich. Möller and P. pseudocoriaceifolius Yan Liu & W. B. Xu, this remarkable new species can be easily distinguished from all other species of Petrocodon s.l. (the two above-mentioned species included) by the shape and color of its memorable corolla. Because of its restricted distribution and threatened environment, the current conservation status of this species should be assessed temporarily as “Endangered.”

Multivariate genome-wide association study of leaf shape in a Populus deltoides and P. simonii F1 pedigree

Leaf morphology exhibits tremendous diversity between and within species, and is likely related to adaptation to environmental factors. Most poplar species are of great economic and ecological values and their leaf morphology can be a good predictor for wood productivity and environment adaptation. It is important to understand the genetic mechanism behind variation in leaf shape. Although some initial efforts have been made to identify quantitative trait loci (QTLs) for poplar leaf traits, more effort needs to be expended to unravel the polygenic architecture of the complex traits of leaf shape. Here, we performed a genome-wide association analysis (GWAS) of poplar leaf shape traits in a randomized complete block design with clones from F1 hybrids of Populus deltoides and Populus simonii. A total of 35 SNPs were identified as significantly associated with the multiple traits of a moderate number of regular polar radii between the leaf centroid and its edge points, which could represent the leaf shape, based on a multivariate linear mixed model. In contrast, the univariate linear mixed model was applied as single leaf traits for GWAS, leading to genomic inflation; thus, no significant SNPs were detected for leaf length, measures of leaf width, leaf area, or the ratio of leaf length to leaf width under genomic control. Investigation of the candidate genes showed that most flanking regions of the significant leaf shape-associated SNPs harbored genes that were related to leaf growth and development and to the regulation of leaf morphology. The combined use of the traditional experimental design and the multivariate linear mixed model could greatly improve the power in GWAS because the multiple trait data from a large number of individuals with replicates of clones were incorporated into the statistical model. The results of this study will enhance the understanding of the genetic mechanism of leaf shape variation in Populus. In addition, a moderate number of regular leaf polar radii can largely represent the leaf shape and can be used for GWAS of such a complicated trait in Populus, instead of the higher-dimensional regular radius data that were previously considered to well represent leaf shape.