Leaf Trichomes Research Articles

Characterization of Microbotryum lychnidis-dioicae Secreted Effector Proteins, Their Potential Host Targets, and Localization in a Heterologous Host Plant.

Microbotryum lychnidis-dioicae is an obligate fungal species colonizing the plant host, Silene latifolia. The fungus synthesizes and secretes effector proteins into the plant host during infection to manipulate the host for completion of the fungal lifecycle. The goal of this study was to continue functional characterization of such M. lychnidis-dioicae effectors. Here, we identified three putative effectors and their putative host-plant target proteins. MVLG_02245 is highly upregulated in M. lychnidis-dioicae during infection; yeast two-hybrid analysis suggests it targets a tubulin α-1 chain protein ortholog in the host, Silene latifolia. A potential plant protein interacting with MVLG_06175 was identified as CASP-like protein 2C1 (CASPL2C1), which facilitates the polymerization of the Casparian strip at the endodermal cells. Proteins interacting with MVLG_05122 were identified as CSN5a or 5b, involved in protein turnover. Fluorescently labelled MVLG_06175 and MVLG_05122 were expressed in the heterologous plant, Arabidopsis thaliana. MVLG_06175 formed clustered granules at the tips of trichomes on leaves and in root caps, while MVLG_05122 formed a band structure at the base of leaf trichomes. Plants expressing MVLG_05122 alone were more resistant to infection with Fusarium oxysporum. These results indicate that the fungus might affect the formation of the Casparian strip in the roots and the development of trichomes during infection as well as alter plant innate immunity.

Characterisation of the R2R3 Myb subgroup 9 family of transcription factors in tomato.

Tomato (Solanum lycopersicum) has many epidermal cell outgrowths including conical petal cells and multiple types of trichomes. These include the anther-specific trichome mesh which holds the anthers connate. The R2R3 Myb Subgroup 9 family of transcription factors is involved in development of epidermal cell outgrowths throughout the angiosperms. No previous study has examined all members of this transcription factor family in a single species. All 7 R2R3 Myb Subgroup 9 genes were isolated from tomato. They were ectopically expressed in tobacco to assess their ability to induce epidermal cell outgrowth. Endogenous expression patterns were examined by semi-quantitative RT-PCR at different stages of floral development relative to the development of anther trichomes. We report variation in the degree of epidermal cell outgrowth produced in transgenic tobacco by each ectopically expressed gene. Based on expression profile and ectopic activity, SlMIXTA-2 is likely involved in the production of leaf trichomes. SlMIXTA-2 is expressed most strongly in the leaves, and not expressed in the floral tissue. SlMYB17-2 is the best candidate for the regulation of the anther trichome mesh. SlMYB17-2 is expressed strongly in the floral tissue and produces a clear phenotype of epidermal cell outgrowths when ectopically expressed in tobacco. Analysis of the phenotypes of transgenic plants ectopically expressing all 7 genes has revealed the different extent to which members of the same transcription factor subfamily can induce cellular outgrowth.

Chemical and transcriptomic analyses of leaf trichomes from Cistus creticus subsp. creticus reveal the biosynthetic pathways of certain labdane-type diterpenoids and their acetylated forms.

Labdane-related diterpenoids (LRDs), a subgroup of terpenoids, exhibit structural diversity and significant commercial and pharmacological potential. LRDs share the characteristic decalin-labdanic core structure that derives from the cycloisomerization of geranylgeranyl diphosphate (GGPP). Labdanes derive their name from the oleoresin known as 'Labdanum', 'Ladano', or 'Aladano', used since ancient Greek times. Acetylated labdanes, rarely identified in plants, are associated with enhanced biological activities. Chemical analysis of Cistus creticus subsp. creticus revealed labda-7,13(E)-dien-15-yl acetate and labda-7,13(E)-dien-15-ol as major constituents. In addition, novel labdanes such as cis-abienol, neoabienol, ent-copalol, and one as yet unidentified labdane-type diterpenoid were detected for the first time. These compounds exhibit developmental regulation, with higher accumulation observed in young leaves. Using RNA-sequencing (RNA-seq) analysis of young leaf trichomes, it was possible to identify, clone, and eventually functionally characterize labdane-type diterpenoid synthase (diTPS) genes, encoding proteins responsible for the production of labda-7,13(E)-dien-15-yl diphosphate (endo-7,13-CPP), labda-7,13(E)-dien-15-yl acetate, and labda-13(E)-ene-8α-ol-15-yl acetate. Moreover, the reconstitution of labda-7,13(E)-dien-15-yl acetate and labda-13(E)-ene-8α-ol-15-yl acetate production in yeast is presented. Finally, the accumulation of LRDs in different plant tissues showed a correlation with the expression profiles of the corresponding genes.

Correlation analysis between artemisinin and its derivative contents and trichome characteristics from different Artemisia species

Artemisia species have significant commercial, medical, and economic value and are widely used in the traditional medicine and pharmaceutical industries. Artemisinin, a powerful antimalarial agent, is an important pharmaceutical metabolite that primarily accumulates within the glandular trichomes (GTs) on the leaf surface of Artemisia plants. Trichomes arising from the elongation of epidermal cells can be classified into GTs and non-glandular trichomes (NGTs) based on their morphology. GTs and NGTs are present in Artemisia species, and the relationship between GTs and artemisinin has been extensively studied; however, the correlation between NGTs and artemisinin remains relatively unexplored. In this study, we inferred artemisinin derivatives and trichome characteristics based on the type of species, developmental stage, and leaf age and conducted correlation analyses to investigate the factors influencing artemisinin content across different Artemisia species. Artemisinin and its derivatives exhibited variations in distribution based on species and leaf age, with a decreasing trend observed across most species as the developmental stage progressed. Noticeable differences among Artemisia species were observed in leaf shape, morphology, and trichome distribution. Although the observed data did not evidently differentiate between species, developmental stage, and leaf age groups, principal component analysis revealed that artemisinin was positively associated with the NGTs density, indicating a correlation coefficient of 0.56 (p < 0.0001). Therefore, the number of NGTs may affect the artemisinin content in different Artemisia species.

HairNet2: deep learning to quantify cotton leaf hairiness, a complex genetic and environmental trait

BackgroundCotton accounts for 80% of the global natural fibre production. Its leaf hairiness affects insect resistance, fibre yield, and economic value. However, this phenotype is still qualitatively assessed by visually attributing a Genotype Hairiness Score (GHS) to a leaf/plant, or by using the HairNet deep-learning model which also outputs a GHS. Here, we introduce HairNet2, a quantitative deep-learning model which detects leaf hairs (trichomes) from images and outputs a segmentation mask and a Leaf Trichome Score (LTS).ResultsTrichomes of 1250 images were annotated (AnnCoT) and a combination of six Feature Extractor modules and five Segmentation modules were tested alongside a range of loss functions and data augmentation techniques. HairNet2 was further validated on the dataset used to build HairNet (CotLeaf-1), a similar dataset collected in two subsequent seasons (CotLeaf-2), and a dataset collected on two genetically diverse populations (CotLeaf-X). The main findings of this study are that (1) leaf number, environment and image position did not significantly affect results, (2) although GHS and LTS mostly correlated for individual GHS classes, results at the genotype level revealed a strong LTS heterogeneity within a given GHS class, (3) LTS correlated strongly with expert scoring of individual images.ConclusionsHairNet2 is the first quantitative and scalable deep-learning model able to measure leaf hairiness. Results obtained with HairNet2 concur with the qualitative values used by breeders at both extremes of the scale (GHS 1-2, and 5-5+), but interestingly suggest a reordering of genotypes with intermediate values (GHS 3-4+). Finely ranking mild phenotypes is a difficult task for humans. In addition to providing assistance with this task, HairNet2 opens the door to selecting plants with specific leaf hairiness characteristics which may be associated with other beneficial traits to deliver better varieties.

Distinguishing Amazonian ipê species (Handroanthus, Bignoniaceae) using macroscopic wood anatomy and leaf morphology

Summary The ipê trees belonging to the genus Handroanthus are among the most exploited species in the Amazon Forest. However, limitations in the wood identification processes can lead to an overexploitation of a single species. We compare, macroscopically, the wood anatomy of five Amazon Handroanthus species (H. barbatus, H. capitatus, H. impetiginosus, H. incanus and H. serratifolius–Bignoniaceae). Except for H. barbatus the species are trees over 20 m tall and are used commercially. We compared leaf morphology of the two most commercially used species (H. impetiginosus and H. serratifolius), aiming to separate them in the field with identification keys. For wood macroscopical analyses, 55 samples were used; the specimens were obtained in the field and from wood collections. The dichotomous key, preferable to be used in a laboratory, enables the distinction of the five species. However, the use of this key requires more knowledge about wood anatomy, since it was necessary to use more quantitative characteristics, due to the great intraspecific variation in Handroanthus woods, also reflected in the PCA (principal components analysis) and grouping analysis. To identify the plant species H. impetiginosus and H. serratifolius, the use of axial parenchyma type and vessel characteristics were important distinguishing factors, while in leaves, the most significant features were characteristics such as leaf margin, trichomes and domatia. In addition, by focusing on these key features, a multiple access identification key was created, which simplified the identification by reducing the number of characteristics necessary for the identification, facilitating its use in the field.

Identification of quantitative trait loci (QTLs) regulating leaf SPAD value and trichome density in mungbean (Vigna radiata L.) using genotyping-by-sequencing (GBS) approach.

Quantitative trait loci (QTL) mapping is used for the precise localization of genomic regions regulating various traits in plants. Two major QTLs regulating Soil Plant Analysis Development (SPAD) value (qSPAD-7-1) and trichome density (qTric-7-2) in mungbean were identified using recombinant inbred line (RIL) populations (PMR-1×Pusa Baisakhi) on chromosome 7. Functional analysis of QTL region identified 35 candidate genes for SPAD value (16 No) and trichome (19 No) traits. The candidate genes regulating trichome density on the dorsal leaf surface of the mungbean include VRADI07G24840, VRADI07G17780, and VRADI07G15650, which encodes for ZFP6, TFs bHLH DNA-binding superfamily protein, and MYB102, respectively. Also, candidate genes having vital roles in chlorophyll biosynthesis are VRADIO7G29860, VRADIO7G29450, and VRADIO7G28520, which encodes for s-adenosyl-L-methionine, FTSHI1 protein, and CRS2-associated factor, respectively. The findings unfolded the opportunity for the development of customized genotypes having high SPAD value and high trichome density having a possible role in yield and mungbean yellow vein mosaic India virus (MYMIV) resistance in mungbean.

Registration of Arkot 1202, Arkot 1207, Arkot 1208, and Arkot 1214 cotton germplasm lines

AbstractArkot 1202 (Reg. no. GP‐1143, PI 702793), Arkot 1207 (Reg. no. GP‐1144, PI 702794), Arkot 1208 (Reg. no. GP‐1145, PI 702795), and ‘Arkot 1214’ (Reg. no. GP‐1146, PI 702796) are conventional cotton (Gossypium hirsutum L.) germplasm lines released by the Arkansas Agricultural Experiment Station in June 2023. Arkot 1202, Arkot 1207, and Arkot 1208 lines share ‘UA48’ (PVP 201100041) as a common parent. The second parent for Arkot 1202 and Arkot 1207 was MD25‐87Y and ‘Columbia’, respectively. The second parent for Arkot 1208 was the F1 of a double cross of F1 (Ark 0219‐15 crossed with LA063071653) and F1 (Arkot 0222 crossed with Ark 0203‐11). Arkot 1214 was derived from a four‐way cross of two double crosses: F1 (MD25‐26ne crossed with Arkot 0113) and F1 (Arkot 0114 crossed with ‘UA222’). In replicated field tests at four Arkansas sites over 5 years, the four lines produced more lint yield than UA48 and UA222. Wide adaptation of the lines was indicated by high lint yields of lines in 2020 regional tests. All four lines displayed high resistance to bacterial blight and Fusarium wilt race 1. Plant (leaf, stem, and bract) trichomes and tarnished plant bug response of Arkot 1202 and Arkot 1214 were equal to UA48, but Arkot 1207 and Arkot 1208 were equal to UA222. Yield component values of the four lines were equal to or better than UA222. The maturity and fiber quality of Arkot 1202 approached that of UA48 while the other three were similar to UA222.

Leaf trichome diversity, acylsugar concentration, and their relationships to leaf area in Solanum galapagense

Glandular trichomes are physical and chemical barriers used by some tomato wild relatives to confer resistance against insect pests and diseases transmitted by them. Solanum galapagense has been identified as one of the potential sources of insect pest resistance. The present study aimed to examine the trichome diversity and acylsugar concentration of 26 accessions of S. galapagense along with one cultivated tomato (S. lycopersicum) and one cherry tomato (S. l. cerasiforme) cultivar. The results revealed large phenotypic variation among S. galapagense accessions for all studied traits. The S. galapagense accessions had significantly higher trichome types IV density on the adaxial and abaxial surfaces of the leaf and greater acylsugar concentration but a smaller leaflet area than the cultivated tomato. The selected cherry tomato line represents greater trichome type IV density and acylsugar concentration than other groups. The acylsugar concentration was positively associated with trichome type IV but negatively associated with trichome type V on both leaf surfaces. DNA markers revealed the presence of two previously identified whitefly-resistance alleles in S. galapagense accessions. This study will support breeding programs aiming to improve insect pest resistance in tomato cultivars using crop wild relatives.

AsHSP26.2, a creeping bentgrass chloroplast small heat shock protein positively regulates plant development.

The creeping bentgrass small heat shock protein AsHSP26.2 positively regulates plant growth and is a novel candidate for use in crop genetic engineering for enhanced biomass production and grain yield. Small heat shock proteins (sHSPs), a family of proteins with high level of diversity, significantly influence plant stress tolerance and plant development. We have cloned a creeping bentgrass chloroplast-localized sHSP gene, AsHSP26.2 responsive to IAA, GA and 6-BA stimulation. Transgenic creeping bentgrass overexpressing AsHSP26.2 exhibited significantly enhanced plant growth with increased stolon number and length as well as enlarged leaf blade width and leaf sheath diameters, but inhibited leaf trichomes initiation and development in the abaxial epidermis. These phenotypes are completely opposite to those displayed in the transgenic plants overexpressing AsHSP26.8, another chloroplast sHSP26 isoform that contains additional seven amino acids (AEGQGDG) between the consensus regions III and IV (Sun et al., Plant Cell Environ 44:1769-1787, 2021). Furthermore, AsHSP26.2 overexpression altered phytohormone biosynthesis and signaling transduction, resulting in elevated auxin and gibberellins (GA) accumulation. The results obtained provide novel insights implicating the sHSPs in plant growth and development regulation, and strongly suggest AsHSP26.2 to be a novel candidate for use in crop genetic engineering for enhanced plant biomass production and grain yield.

The Kazakh University Common Bean Collection: The Introductory Trial of Snaps

The aim of the present investigation was to determine the introduction power of the three snap common bean cultivars from the UK in the mountainous zone of Almaty Region in 2023. The harvest-time, plant and leaf growth dynamics, the state of leaf trichomes together with the productivity of snaps at the technical maturity were identified. Cultivars “Amethyst” and “Seline” were shown to be the appropriate snap breeding donors for local bush bean lines due to their parameters of seed germination and plant leaf size together with their trichome parameters resembling those of domestic lines under the study.

Interplay of EXO70 and MLO proteins modulates trichome cell wall composition and susceptibility to powdery mildew.

Exocyst component of 70-kDa (EXO70) proteins are constituents of the exocyst complex implicated in vesicle tethering during exocytosis. MILDEW RESISTANCE LOCUS O (MLO) proteins are plant-specific calcium channels and some MLO isoforms enable fungal powdery mildew pathogenesis. We here detected an unexpected phenotypic overlap of Arabidopsis thaliana exo70H4 and mlo2 mlo6 mlo12 triple mutant plants regarding the biogenesis of leaf trichome secondary cell walls. Biochemical and Fourier transform infrared spectroscopic analyses corroborated deficiencies in the composition of trichome cell walls in these mutants. Transgenic lines expressing fluorophore-tagged EXO70H4 and MLO exhibited extensive colocalization of these proteins. Furthermore, mCherry-EXO70H4 mislocalized in trichomes of the mlo triple mutant and, vice versa, MLO6-GFP mislocalized in trichomes of the exo70H4 mutant. Expression of GFP-marked PMR4 callose synthase, a known cargo of EXO70H4-dependent exocytosis, revealed reduced cell wall delivery of GFP-PMR4 in trichomes of mlo triple mutant plants. In vivo protein-protein interaction assays in plant and yeast cells uncovered isoform-preferential interactions between EXO70.2 subfamily members and MLO proteins. Finally, exo70H4 and mlo6 mutants, when combined, showed synergistically enhanced resistance to powdery mildew attack. Taken together, our data point to an isoform-specific interplay of EXO70 and MLO proteins in the modulation of trichome cell wall biogenesis and powdery mildew susceptibility.

A eudicot MIXTA family ancestor likely functioned in both conical cells and trichomes.

The MIXTA family of MYB transcription factors modulate the development of diverse epidermal features in land plants. This study investigates the evolutionary history and function of the MIXTA gene family in the early-diverging eudicot model lineage Thalictrum (Ranunculaceae), with R2R3 SBG9-A MYB transcription factors representative of the pre-core eudicot duplication and thus hereby referred to as "paleoMIXTA" (PMX). Cloning and phylogenetic analysis of Thalictrum paleoMIXTA (ThPMX) orthologs across 23 species reveal a genus-wide duplication coincident with a whole-genome duplication. Expression analysis by qPCR confirmed that the highest expression is found in carpels, while newly revealing high expression in leaves and nuanced differences between paralogs in representative polyploid species. The single-copy ortholog from the diploid species T. thalictroides (TthPMX, previously TtMYBML2), which has petaloid sepals with conical-papillate cells and trichomes on leaves, was functionally characterized by virus-induced gene silencing (VIGS), and its role in leaves was also assessed from heterologous overexpression in tobacco. Another ortholog from a species with conical-papillate cells on stamen filaments, TclPMX, was also targeted for silencing. Overexpression assays in tobacco provide further evidence that the paleoMIXTA lineage has the potential for leaf trichome function in a core eudicot. Transcriptome analysis by RNA-Seq on leaves of VIGS-treated plants suggests that TthPMX modulates leaf trichome development and morphogenesis through microtubule-associated mechanisms and that this may be a conserved pathway for eudicots. These experiments provide evidence for a combined role for paleoMIXTA orthologs in (leaf) trichomes and (floral) conical-papillate cells that, together with data from other systems, makes the functional reconstruction of a eudicot ancestor most likely as also having a combined function.

Efecto de antibiosis, antixenosis y la variación natural de tricomas de especies silvestres y comerciales en tomate sobre el desarrollo de Bactericera cockerelli

Bactericera cockerelli is an economically relevant pest of solanaceous crops. The presence of leaf trichomes that certain wild species have constitutes important genetic resources for plant breeding programs in terms of resistance to pests. In this study, the influence of leaf trichomes of wild species and commercial tomato cultivars on the preference, development and fecundity of B. cockerelli was evaluated. The results showed that wild species were less preferred by the psyllid than commercial cultivars. Insects showed a lower settlement percentage in S. habrochaites compared to the other species. Regarding survival, the lowest percentage developed in S. habrochaites with 24% and S. arcanum with 40%. The lowest oviposition average was found in S. habrochaites with two eggs, which did not hatch, in addition to being the only species that showed the presence of glandular trichomes type IV (113.86 ± 48.1) and VIc (27.3 ± 2.3) per mm2, and its presence was negatively correlated with the number of perched adults. S. arcanum was another species that negatively influenced the behavior and development of the insects; however, these attributes were not due to the presence of trichomes. The defense mechanisms expressed by S. habrochaites and S. arcanum towards B. cockerelli can be used as a resource for gene introgression for the management of this pest by reducing its biological potential.

Pollinator and habitat-mediated selection as potential contributors to ecological speciation in two closely related species.

In ecological speciation, incipient species diverge due to natural selection that is ecologically based. In flowering plants, different pollinators could mediate that selection (pollinator-mediated divergent selection) or other features of the environment that differ between habitats of 2 species could do so (environment-mediated divergent selection). Although these mechanisms are well understood, they have received little rigorous testing, as few studies of divergent selection across sites of closely related species include both floral traits that influence pollination and vegetative traits that influence survival. This study employed common gardens in sites of the 2 parental species and a hybrid site, each containing advanced generation hybrids along with the parental species, to test these forms of ecological speciation in plants of the genus Ipomopsis. A total of 3 vegetative traits (specific leaf area, leaf trichomes, and photosynthetic water-use efficiency) and 5 floral traits (corolla length and width, anther insertion, petal color, and nectar production) were analyzed for impacts on fitness components (survival to flowering and seeds per flower, respectively). These traits exhibited strong clines across the elevational gradient in the hybrid zone, with narrower clines in theory reflecting stronger selection or higher genetic variance. Plants with long corollas and inserted anthers had higher seeds per flower at the Ipomopsis tenuituba site, whereas selection favored the reverse condition at the Ipomopsis aggregata site, a signature of divergent selection. In contrast, no divergent selection due to variation in survival was detected on any vegetative trait. Selection within the hybrid zone most closely resembled selection within the I. aggregata site. Across traits, the strength of divergent selection was not significantly correlated with width of the cline, which was better predicted by evolvability (standardized genetic variance). These results support the role of pollinator-mediated divergent selection in ecological speciation and illustrate the importance of genetic variance in determining divergence across hybrid zones.

Engineering custom morpho- and chemotypes of Populus for sustainable production of biofuels, bioproducts, and biomaterials.

Humans have been modifying plant traits for thousands of years, first through selection (i.e., domestication) then modern breeding, and in the last 30 years, through biotechnology. These modifications have resulted in increased yield, more efficient agronomic practices, and enhanced quality traits. Precision knowledge of gene regulation and function through high-resolution single-cell omics technologies, coupled with the ability to engineer plant genomes at the DNA sequence, chromatin accessibility, and gene expression levels, can enable engineering of complex and complementary traits at the biosystem level. Populus spp., the primary genetic model system for woody perennials, are among the fastest growing trees in temperate zones and are important for both carbon sequestration and global carbon cycling. Ample genomic and transcriptomic resources for poplar are available including emerging single-cell omics datasets. To expand use of poplar outside of valorization of woody biomass, chassis with novel morphotypes in which stem branching and tree height are modified can be fabricated thereby leading to trees with altered leaf to wood ratios. These morphotypes can then be engineered into customized chemotypes that produce high value biofuels, bioproducts, and biomaterials not only in specific organs but also in a cell-type-specific manner. For example, the recent discovery of triterpene production in poplar leaf trichomes can be exploited using cell-type specific regulatory sequences to synthesize high value terpenes such as the jet fuel precursor bisabolene specifically in the trichomes. By spatially and temporally controlling expression, not only can pools of abundant precursors be exploited but engineered molecules can be sequestered in discrete cell structures in the leaf. The structural diversity of the hemicellulose xylan is a barrier to fully utilizing lignocellulose in biomaterial production and by leveraging cell-type-specific omics data, cell wall composition can be modified in a tailored and targeted specific manner to generate poplar wood with novel chemical features that are amenable for processing or advanced manufacturing. Precision engineering poplar as a multi-purpose sustainable feedstock highlights how genome engineering can be used to re-imagine a crop species.

How the Adequate Choice of Plant Species Favors the Restoration Process in Areas Susceptible to Extreme Frost Events.

This work aimed to evaluate the impacts caused by extreme frost events in an ecological restoration area. We grouped the species in three ways: (1) type of trichome coverage; (2) shape of the seedling crown; and (3) functional groups according to the degree of damage caused by frost. The variables of the restored area and species characteristics were selected to be subjected to linear generalization analysis models (GLMs). A total of 104 individuals from seven species were sampled. The most affected species were Guazuma ulmifolia Lam. (98% of leaves affected), followed by Cecropia pachystachia Trécul and Hymenea courbaril L. (both 97%), Inga vera Willd. (84%), and Senegalia polyphylla (DC.) Britton & Rose with 75%. Tapirira guianensis Aubl. was considered an intermediate species, with 62% of the crown affected. Only Solanum granulosoleprosum Dunal was classified as slightly affected, with only 1.5% of leaves affected. With the GLM analysis, it was verified that the interaction between the variables of leaf thickness (Χ² = 37.1, df = 1, p < 0.001), trichome coverage (Χ² = 650.5, df = 2, p < 0.001), and leaf structure culture (Χ² = 54.0, df = 2, p < 0.001) resulted in a model with high predictive power (AIC = 927,244, BIC = 940,735, Χ² = 6947, R² = 0.74, p < 0.001). Frost-affected crown cover was best explained by the interaction between the three functional attributes (74%). We found that there is a tendency for thicker leaves completely covered in trichomes to be less affected by the impact of frost and that the coverage of the affected crown was greatly influenced by the coverage of trichomes. Seedlings with leaves completely covered in trichomes, thicker leaves, and a funneled or more open crown structure are those that are most likely to resist frost events. The success of ecological restoration in areas susceptible to extreme events such as frost can be predicted based on the functional attributes of the chosen species. This can contribute to a better selection of species to be used to restore degraded areas.

Morphological Characterization of Cannabis sativa L. Throughout Its Complete Life Cycle.

This study extensively characterizes the morphological characteristics, including the leaf morphology, plant structure, flower development, and trichome features throughout the entire life cycle of Cannabis sativa L. cv. White Widow. The developmental responses to photoperiodic variations were investigated from germination to mature plant senescence. The leaf morphology showed a progression of complexity, beginning with serrations in the 1st true leaves, until the emergence of nine leaflets in the 6th true leaves, followed by a distinct shift to eight, then seven leaflets with the 14th and 15th true leaves, respectively. Thereafter, the leaf complexity decreased, culminating in the emergence of a single leaflet from the 25th node. The leaf area peaked with the 12th leaves, which coincided with a change from opposite to alternate phyllotaxy. The stipule development at nodes 5 and 6 signified the vegetative phase, followed by bract and solitary flower development emerging in nodes 7-12, signifying the reproductive phase. The subsequent induction of short-day photoperiod triggered the formation of apical inflorescence. Mature flowers displayed abundant glandular trichomes on perigonal bracts, with stigma color changing from whitish-yellow to reddish-brown. A pronounced increase in trichome density was evident, particularly on the abaxial bract surface, following the onset of flowering. The trichomes exhibited simultaneous growth in stalk length and glandular head diameter and pronounced shifts in color. Hermaphroditism occurred well after the general harvest date. This comprehensive study documents the intricate photoperiod-driven morphological changes throughout the complete lifecycle of Cannabis sativa L. cv. White Widow. The developmental responses characterized provide valuable insights for industrial and research applications.

Impact of leaf trichomes of tomatoes and weeds on the host selection and developmental bioassays of Bemisia tabaci Q and A cryptic species

The whiteflies of Bemisia tabaci complex, composed of >44 cryptic species, are economically important pests of tomatoes for their direct feeding and virus transmission. The present study aimed to evaluate the impact of leaf trichomes on the host selection and development of whitefly; comparative invasiveness between B. tabaci Q and A cryptic species; and the ability of weeds as hosts of the population of insect whitefly. We carried out our investigation through adult host selection and oviposition in multi-choice conditions, immature development and survival, and adult survival and oviposition in no-choice conditions. We investigated leaf trichomes type and densities on the leaves of four tomato varieties and two weed species. Results showed that the leaf trichomes of tomatoes and weeds impact the host selection and immature development differently on the cryptic species B. tabaci Q and A. In the multi-choice case, B. tabaci Q adults preferred tomato varieties Ao-Ni-Er and He-Fen for both settling and oviposition whereas B. tabaci A preferred Ao-Ni-Er, He-Fen, and Billy-Goat-Weed for settling but oviposited more eggs on both weed species Billy-Goat-Weed and False-Mallow. Both B. tabaci Q and A adults refused Ye-Sheng either settling or oviposition. In the case of immature development, B. tabaci Q developed faster than B. tabaci A. Concerning plant, B. tabaci Q developed faster on Ao-Ni-Er, He-Fen and Billy-Goat-Weed but B. tabaci A on Billy-Goat-Weed, False-Mallow and Ao-Ni-Er. The immature survival of Q was higher than that of A. Immature of B. tabaci Q survived well (68.6–86.8%) on all plants except Ye-Sheng (49.3%) but B. tabaci A survived very less (0–17.6%) on any tomatoes where 70.4% on Billy-Goat-Weed and 60.5% on False-Mallow. After seven days of adult infestation, both B. tabaci Q and A died on Ye-Sheng where 52.5–78.1% survivorships were observed on other plants. In seven days, B. tabaci Q laid more eggs compared to B. tabaci A. Considering the plants, both species laid more eggs on Ao-Ni-Er, He-Fen and False-Mallow, whereas the lowest number was laid on Ye-Sheng. The highest number of glandular trichome Type IV was observed on Ye-Sheng which showed resistance against both B. tabaci Q and A cryptic species. The cryptic species B. tabaci Q showed a wider range adaptation ability on plants than that of A. Weeds can play a significant role as an infestation source of whiteflies to tomatoes and other crops. These findings suggest that glandular trichomes may be used in plant breeding programmes for the development of whitefly-resistant crop cultivars.

Comparative morphoanatomy and transcriptomic analyses reveal key factors controlling floral trichome development in Aristolochia (Aristolochiaceae).

Trichomes are specialized epidermal cells in aerial plant parts. Trichome development proceeds in three stages, determination of cell fate, specification, and morphogenesis. Most genes responsible for these processes have been identified in the unicellular branched leaf trichomes from the model Arabidopsis thaliana. Less is known about the molecular basis of multicellular trichome formation across flowering plants, especially those formed in floral organs of early diverging angiosperms. Here, we aim to identify the genetic regulatory network (GRN) underlying multicellular trichome development in the kettle-shaped trap flowers of Aristolochia (Aristolochiaceae). We selected two taxa for comparison, A. fimbriata, with trichomes inside the perianth, which play critical roles in pollination, and A. macrophylla, lacking specialized trichomes in the perianth. A detailed morphoanatomical characterization of floral epidermis is presented for the two species. We compared transcriptomic profiling at two different developmental stages in the different perianth portions (limb, tube, and utricle) of the two species. Moreover, we present a comprehensive expression map for positive regulators and repressors of trichome development, as well as cell cycle regulators. Our data point to extensive modifications in gene composition, expression, and putative roles in all functional categories when compared with model species. We also record novel differentially expressed genes (DEGs) linked to epidermis patterning and trichome development. We thus propose the first hypothetical genetic regulatory network (GRN) underlying floral multicellular trichome development in Aristolochia, and pinpoint key factors responsible for the presence and specialization of floral trichomes in phylogenetically distant species of the genus.