Anther Filaments Research Articles

Green Revolution dwarfing Rht genes negatively affected wheat floral traits related to cross-pollination efficiency.

Hybrid breeding is a promising strategy to quickly improve wheat yield and stability. Due to the usefulness of the Rht 'Green Revolution' dwarfing alleles, it is important to gain a better understanding of their impact on traits related to hybrid development. Traits associated with cross-pollination efficiency were studied using Near Isogenic Lines carrying the different sets of alleles in Rht genes: Rht1 (semi-dwarf), Rht2 (semi-dwarf), Rht1 + 2 (dwarf), Rht3 (extreme dwarf), Rht2 + 3 (extreme dwarf), and rht (tall) during four growing seasons. Results showed that the extreme dwarfing alleles Rht2 + 3, Rht3, and Rht1 + 2 presented the greatest effects in all the traits analyzed. Plant height showed reductions up to 64% (Rht2 + 3) compared to rht. Decreases up to 20.2% in anther length and 33% in filament length (Rht2 + 3) were observed. Anthers extrusion decreased from 40% (rht) to 20% (Rht1 and Rht2), 11% (Rht3), 8.3% (Rht1 + 2), and 6.5% (Rht2 + 3). Positive correlations were detected between plant height and anther extrusion, anther, and anther filament lengths, suggesting the negative effect of dwarfing alleles. Moreover, the magnitude of these negative impacts depends on the combination of the alleles: Rht2 + 3 > Rht3/Rht1 + 2 > Rht2/Rht1 > rht (tall). Reductions were consistent across genotypes and environments with interactions due to magnitude effects. Our results indicate that Rht alleles are involved in multiple traits of interest for hybrid wheat production and the need to select alternative sources for reduced height/lodging resistance for hybrid breeding programs.

RHODODENDRON ASTROPHORUM (ERICACEAE, RHODODENDRON SECT. SCHISTANTHE), A NEW MICRO-ENDEMIC SPECIES FROM CENTRAL PALAWAN, PHILIPPINES

A new micro-endemic species of Rhododendron is described and illustrated from botanical expeditions to the Victoria-Anepahan Mountain Range on the island of Palawan. It closely resembles Rhododendron wilkiei but differs in having leaves with laminae that are narrowly elliptic-oblanceolate, have adaxially indistinct venation, and are arranged in 4–8 active and mostly terminal pseudowhorls along the length of the stem; bracts without scales on the margin; yellow flowers with a red corolla tube interior that is densely hairy towards the base; and hairy anther filament bases. Morphological and geographical data place the species in Rhododendron sect. Schistanthe. The new species, together with a first record of Rhododendron vidalii on Palawan as part of this research, represent the tenth and eleventh members of this genus recorded from the island. A revised key to the Palawan species of Rhododendron is provided.

Floral and reproductive biology of Commelina erecta L. (Commelinaceae) in a coastal dune system on the Gulf of Mexico

The most common sexual systems found in Commelinaceae species are hermaphroditic and andromonoecious, and although enantiostyly is also recognized in the family, it has only been recorded in a few species. The presence of different sexual systems (v.gr., andromonoecious and enantiostyly) in the same species is still unnoted. Commelina erecta is a common andromonoecious-enantiostylous species (i.e., it bears male, left-styled and right-styled flowers) of the coastal dunes of La Mancha in Veracruz, Mexico. Our aims were to determine: (1) the type of enantiostyly, (2) the floral morph-ratios in a population, (3) the differences in size of flowers structures among floral morphs, to (4) characterize the floral visitor community in the different floral morphs, and (5) evaluate differences in fruit set in the hermaphroditic flowers. We found that C. erecta in La Mancha is characterized by non-reciprocal monomorphic enantiostyly. The proportion of floral morphs varied among sampling months. Discriminant analysis and a Wilcoxon test using canonical scores indicated that the anther area and filament length of male flowers are larger in size than those in hermaphroditic flowers. In total, we recorded 220 visits to the flowers of C. erecta by 18 species of insects belonging to five orders. Our study shows that the main floral visitor was the halictid bee Augoclorella sp. Left- and right-styled flowers were equally successful in terms of producing fruits and seeds of the same weight and size, but overall reproductive success was low, with fruit set of only 29%.

Ultrastructural study of anther parasitism of Ficus laevigata by Ficophagus laevigatus (Aphelenchoididae).

Transmission electron microscopy (TEM) was used to compare the ultrastructural differences between healthy male florets (anthers) and one floret parasitized by Ficophagus laevigatus in late phase C syconia of Ficus laevigata from southern Florida. Previous light-microscopic examination of paraffin-sectioned material showed that F. laevigatus-infested anthers of F. laevigata manifested as malformed, often with aberrant pollen and hypertrophied epidermal cells closest to regions containing propagating nematodes. Female florets or fig wasp-parasitized female florets were not observed to be parasitized by nematodes. Considering that plant-feeding in the Aphelenchoididae is purportedly much less specialized than in certain groups of the Tylenchomorpha, where specialized hypertrophied feeder cells are produced in response to nematode feeding, we examined the putative induced response in this unusual aphelenchoidid system with the higher resolution afforded by TEM. TEM confirmed the expression of significant epidermal cell hypertrophy of the anther and anther filament in the presence of propagating nematodes, which was expressed as cell enlargement (2-5X), fractionation of large electron-dense stores into smaller aggregates, irregularly shaped nuclei enclosed by an elongated nuclear envelope, nucleolus enlargement, increased organelle production, and apparent metabolism with increased numbers of mitochondria, pro-plastids, and endoplasmic reticulum, as well as increased thickening of the cell walls. Pathological effects were observed in adjacent cells/tissue (e.g., anther and anther filament parenchymal cells, pollen tubes, pollen, and endothecium) with apparent diminishment as the distance from propagating nematodes increased (which was also probably affected by number of nematodes). Some TEM sections captured previously undocumented ultrastructural highlights of propagating individuals of F. laevigatus.

Miconia amplipedunculata (Melastomataceae: Miconieae), a new species from the Caribbean lowlands of Panama

Miconia amplipedunculata is described as a new species that is known from a limited area in the Caribbean lowland rainforests of Panama. Line drawings, field photographs, a distribution map, and a comparative discussion of morphologically similar species are provided. This species is readily distinguished by its short-petiolate alternately 3-plinerved leaf blades, brown amorphous stellulate-lepidote indumentum on the primary and secondary veins of abaxial foliar surfaces and inflorescence, long-pedunculate (up to 12.5 cm) inflorescence, persistent bracts and bracteoles, unlobed truncate calyx, prominent subulate calyx teeth that exceed the calyx, 5-merous flowers, distally constricted anther filaments, and isometric and isomorphic stamens that lack appendages. The new species is compared with M. iteophylla, M. jefensis, M. ligulata, and M. peltata. All of these species, except M. ligulata, are also endemic to Panama.

Comparative Morpho-micrometric Investigations in Six Indigenous Ocimum Species of India with DOE Based HPTLC Method for Multi-class Component Analysis.

The Ocimum genus is one of India's prominent botanical classes of traditional medicinal culture comprising medicinally and agronomically important plants. Morphological resemblances, overlapping geographical distribution, and history of traditional nomenclature have necessitated a comprehensive qualitative report for effective quality control and removing the species ambiguity pertaining to this genus. This paper provides detailed morpho-micrometric characteristics used to differentiate between six indigenous Ocimum species of India. Among them, O. gratissimum was distinguished as the only shrub with a fleshy petiole. In green and purple forms, O. tenuiflorum leaves had serrate margins and showed no particular anatomical differences except for the anthocyanins containing epidermal cells of the latter. O. basilicum had glabrous leaves except for the veins, which were puberulous. O. filamentosum had tenuous anther filaments and was the least aromatic while O. africanum had a citrusy odour, which along with the number of xylary rows, size of mesophyll cells, and epidermal cell wall architecture, distinguished it from O.americanum. An HPTLC method was developed using experimental design and validated for quantification of multi-class compounds from terpenoic, phenolic acids, and flavonoids in Ocimum leaves. It was found linear (r 2 > 0.99) with recoveries between 95 - 100% for all compounds. The eluted bands of marker compounds were subjected to HPTLC-MS analysis as a confirmative tool. This is the first anatomical and analytical report of O. filamentosum Forssk. The obtained results could be effectively used for species identification using vegetative characters alone with the anatomical-HPTLC data backing up the former as a rapid and economical tool.

Полиморфизм признаков цветка и плода яблони Цуми (Malus zumi (Matsum.) Rehder)

The Tsumi apple tree is a valuable crop due to the presence of a gene for resistance to powdery mildew, abundant annual fruiting and a special decorative effect during flowering and fruiting. Its breeding potential has been little studied; therefore, it is necessary to study the morphometric characteristics of a flower and a fruit and establish connections between them. The collection of flowers and fruits of the Tsumi apple tree was carried out in the laboratory of cultivated plants of the Tsytsin Main Botanical Garden in 2021. The coefficients of variation and correlation according to Spearman were determined. It was found that the polymorphism of flower traits is at a very low level (from 4.4% to 14.2%). The number of flowers per inflorescence varies within 15.9%, which corresponds to the average level of polymorphism, as well as in the weight of the fruit (17.3%) and in the weight of seeds (19.5%). Variations in the length of the peduncle, the number of seeds, the length of the fruit, and the diameter of the fruit are at a very low level (6.9-13.6%). A significant number of reliable inverse (negative) correlations were found between signs of moderate strength (0.5 <r <0.6): a strong relationship between fruit weight and anther length (r = -0.73), fruit length and filament length (r = -0.71). A strong positive relationship was found between the following traits: fruit weight and fruit diameter (r = 0.79), seed weight. Keywords: POLYMORPHISM, FLOWER, CRABAPPLES, SORBOMALUS, MALUS ZUMI, TSUMI APPLE TREE, VARIABILITY, MORPHOLOGY

Effect of the light and dark conditions on flower opening time between cultivated rice (Oryza sativa) and a near-isogenic early-morning flowering line.

Flower opening time (FOT) is affected by genetic and environmental factors, but little is known about the effect of light and dark conditions on FOT in cereal crops. FOT of an indica rice cultivar, IR64, and its near-isogenic line carrying a QTL for an early-morning flowering trait (IR64+qEMF3) were investigated in a natural-light and temperature-controlled small greenhouse by exposing either the panicle or stem or both plant organs to different light and dark conditions. FOT did not change in either genotype when panicles were exposed to light. A large difference in FOT was found between genotypes when panicles were exposed to dark conditions; no flower opening was observed in IR64, whereas flower opening was delayed but observed in IR64+qEMF3. These results suggest that the panicle is the organ that perceives light for flower opening in both genotypes, whereas the light requirement to reach flower opening was quite different between genotypes. Flower opening of IR64 occurred concomitantly with elongation of anther filament in the light after the dark treatment stopped, whereas approximately half of flowering of IR64+qEMF3 resulted in apparent cleistogamy even during dark treatment. An extended duration of the dark treatment until 1730H (30–50 min before sunset) made FOT of IR64 spikelets on the next day shifted to a time as early as that of IR64+qEMF3, with significant advancement of FOT compared to the control IR64 spikelets. Our results indicated that different flowering responses to light and dark conditions exist between IR64 and IR64+qEMF3. These findings provide clues for understanding the unique genetic controls of flowering in an EMF line in rice. This study also showed evidence that artificial light environments can shift the FOT of IR64 to that of IR64+qEMF3.

Genetic factors associated with favourable pollinator traits in the wheat cultivar Piko.

Hybrid breeding in wheat has the potential to boost yields. An efficient hybrid seed production system requires elite pollinators; however, such germplasm is limited among modern cultivars. Piko, a winter wheat (Triticum aestivum L.) cultivar, has been identified as a superior pollinator and has been used in Europe. Piko has favourable pollinator traits for anther extrusion, anther length, pollen mass and hybrid seed set. However, the genetic factors responsible for Piko's favourable traits are largely unknown. Here, we report on the genetic analysis of a Piko-derived F2 mapping population. We confirmed that Piko's Rht-D1a allele for tall stature is associated with large anthers and high anther extrusion. However, Rht-D1 was not found to be associated with anther filament length, confirmed by near isogenic lines. Piko's photoperiod sensitive Ppd-B1b allele shows an association with increased spike length, more spikelets and spike architecture traits, while the insensitive Ppd-B1a allele is linked with high anther extrusion and larger anthers. We identified an anther extrusion quantitative trait locus (QTL) on chromosome 6A that showed significantly biased transmission of the favourable Piko allele amongst F2 progenies. The Piko allele is completely absent in the distal 6AS region and the central 6A region revealed a significantly lower ratio (<8%) of F2 with homozygous Piko alleles. Our study provided further evidence for the effects of Rht-D1 and Ppd-B1 loci on multiple pollinator traits and a novel anther extrusion QTL that exhibits segregation distortion.

Taxonomic significance of stamens and pollen morphology of some selected taxa of Primulaceae in Egypt

Abstract The circumscription study of Primulaceae is still uncertain and remains controversial. Stamens and pollen grains morphological characters of five species and one variety representing five genera viz.,Anagallis, Lysimachia, Coris, Primula and Samolus of Primulaceae in Egypt have been studied using LM and SEM. The specific target of the present study is to evaluate the taxonomic value of the macro and micromorphological characters of stamens and pollen grains in order to distinguish between the studied species. The obtained results showed remarkable variations in anther shape, anther dehiscence, filament attachment and presence of trichomes on the anther filament. Pollen grains are radially symmetrical, isopolar, spheroidal-subprolate to prolate, with amb angulaperturate or fossaperturate and tricolpate or tricolporate. Tectum is microreticulate, reticulate with perforated lumine and clavate exine ornamentation. Out of the studied taxa Coris monspeliensis is distinguished by the presence of prominent margo, reticulate exine ornamentation, minute luminal perforations decreasing towards the colpi, orbicular anther shape, latrorse dehiscence of anthers with short longitudinal slit and presence of glandular diseriate trichomes at the base of the filaments. Clavate exine ornamentation as well as lanceolate anther shape, extrorse dehiscence and short filament can distinguished Samolus valerandi from the remaining studied taxa. An artificial key for the studied species was constructed based on stamens and pollen morphological criteria is provided.

The genus Adoxa L. (Adoxaceae Trautv.) in the flora of Russia

In this paper, species of the genus Adoxa L. were analyzed that occur in the flora of Russia. We noted that three species have been found on the territory of Russia: Adoxa moschatellina L., Adoxa orientalis Nepomn. and Adoxa insularis Nepomn. A. moschatellina has a circumpolar areal. The species A. orientalis rarely occurs in Far East. It was determined that this species has more primitive flower structure as compared with A. moschatellina. The lateral flowers of A. orientalis in the inflorescence are trimerous (Ca(3)CO(6)A6G(3)),, whereas anther filaments are integral. On islands Kunashir and Sakhalin, we noted the presence of A. insularis whose flower structure has signs of more complete organization. In A. insularis, petals are oval, with a pointed tip, and have straight veinlets; A. insularis possesses 3- to 4-fold fewer nectar glandules, which are located directly on the petals’ surface, rather than in depressions on the petals as in A. moschatellina. Anther filaments in A. insularis are longer, and the angle between cleft filaments in A. insularis is 30–40° (rather than 90° or more as in A. moschatellina). It was concluded that in Adoxa species, there has been an obvious process of evolutionary reduction of flower structure.

Effects on Plant Growth and Reproduction of a Peach R2R3-MYB Transcription Factor Overexpressed in Tobacco.

In plants, anthocyanin production is controlled by MYB and bHLH transcription factors. In peach, among the members of these families, MYB10.1 and bHLH3 have been shown to be the most important genes for production of these pigments during fruit ripening. Anthocyanins are valuable molecules, and the overexpression of regulatory genes in annual fast-growing plants has been explored for their biotechnological production. The overexpression of peach MYB10.1 in tobacco plants induced anthocyanin pigmentation, which was particularly strong in the reproductive parts. Pigment production was the result of an up-regulation of the expression level of key genes of the flavonoid biosynthetic pathway, such as NtCHS, NtCHI, NtF3H, NtDFR, NtANS, and NtUFGT, as well as of the proanthocyanidin biosynthetic pathway such as NtLAR. Nevertheless, phenotypic alterations in transgenic tobacco lines were not only limited to anthocyanin production. Lines showing a strong phenotype (type I) exhibited irregular leaf shape and size and reduced plant height. Moreover, flowers had reduced length of anther’s filament, nondehiscent anthers, reduced pistil length, aborted nectary glands, and impaired capsule development, but the reproductive parts including androecium, gynoecium, and petals were more pigmented that in wild type. Surprisingly, overexpression of peach MYB10.1 led to suppression of NtMYB305, which is required for floral development and, of one of its target genes, NECTARIN1 (NtNCE1), involved in the nectary gland formation. MYB10.1 overexpression up-regulated JA biosynthetic (NtAOS) and signaling (NtJAZd) genes, as well as 1-aminocyclopropane-1-carboxylate oxidase (NtACO) in flowers. The alteration of these hormonal pathways might be among the causes of the observed floral abnormalities with defects in both male and female gametophyte development. In particular, approximately only 30% of pollen grains of type I lines were viable, while during megaspore formation, there was a block during FG1 (St3-II). This block seemed to be associated to an excessive accumulation of callose. It can be concluded that the overexpression of peach MYB10.1 in tobacco not only regulates flavonoid biosynthesis (anthocyanin and proanthocyanidin) in the reproductive parts but also plays a role in other processes such as vegetative and reproductive development.

A comparison of coffee floral traits under two different agricultural practices

Floral traits and rewards are important in mediating interactions between plants and pollinators. Agricultural management practices can affect abiotic factors known to influence floral traits; however, our understanding of the links between agricultural practices and floral trait expression is still poorly understood. Variation in floral morphological, nectar, and pollen traits of two important agricultural species, Coffea arabica and C. canephora, was assessed under different agricultural practices (sun and shade). Corolla diameter and corolla tube length were larger and pollen total nitrogen content greater in shade plantations of C. canephora than sun plantations. Corolla tube length and anther filament length were larger in shade plantations of C. arabica. No effect of agricultural practice was found on nectar volume, sugar or caffeine concentrations, or pollen production. Pollen total nitrogen content was lower in sun than shade plantations of C. canephora, but no difference was found between sun and shade for C. arabica. This study provides baseline data on the influence of agronomic practices on C. arabica and C. canephora floral traits and also helps fill a gap in knowledge about the effects of shade trees on floral traits, which can be pertinent to other agroforestry systems.

PACLOBUTRAZOL-RESISTANCE Gene Family Regulates Floral Organ Growth with Unequal Genetic Redundancy in Arabidopsis thaliana.

A PACLOBUTRAZOL-RESISTANCE (PRE) gene family, consisting of six genes in Arabidopsis thaliana, encodes a group of helix-loop-helix proteins that act in the growth-promoting transcriptional network. To delineate the specific role of each of the PRE genes in organ growth, we took a reverse genetic approach by constructing high order pre loss-of-function mutants of Arabidopsis thaliana. In addition to dwarf vegetative growth, some double or high order pre mutants exhibited defective floral development, resulting in reduced fertility. While pre2pre5 is normally fertile, both pre2pre6 and pre5pre6 showed reduced fertility. Further, the reduced fertility was exacerbated in the pre2pre5pre6 mutant, indicative of the redundant and critical roles of these PREs. Self-pollination assay and scanning electron microscopy analysis showed that the sterility of pre2pre5pre6 was mainly ascribed to the reduced cell elongation of anther filament, limiting access of pollens to stigma. We found that the expression of a subset of flower-development related genes including ARGOS, IAA19, ACS8, and MYB24 was downregulated in the pre2pre5pre6 flowers. Given these results, we propose that PREs, with unequal functional redundancy, take part in the coordinated growth of floral organs, contributing to successful autogamous reproduction in Arabidopsis thaliana.

Identification and functional analysis of three new anthocyanin R2R3-MYB genes in Petunia.

We identified three novel members of the R2R3‐MYB clade of anthocyanin regulators in the genome of the purple flowering Petunia inflata S6 wild accession, and we called them ANTHOCYANIN SYNTHESIS REGULATOR (ASR). Two of these genes, ASR1 and ASR2, are inactivated by two different single base mutations in their coding sequence. All three of these genes are absent in the white flowering species P. axillaris N and P. parodii, in the red flowering P. exserta, and in several Petunia hybrida lines, including R27 and W115. P. violacea and other P. hybrida lines (M1, V30, and W59) instead harbor functional copies of the ASR genes. Comparative, functional and phylogenic analysis of anthocyanin R2R3‐MYB genes strongly suggest that the ASR genes cluster is a duplication of the genomic fragment containing the other three R2R3‐MYB genes with roles in pigmentation that were previously defined, the ANTHOCYANIN4‐DEEP PURPLE‐PURPLE HAZE (AN4‐DPL‐PHZ) cluster. An investigation of the genomic fragments containing anthocyanin MYBs in different Petunia accessions reveals that massive rearrangements have taken place, resulting in large differences in the regions surrounding these genes, even in closely related species. Yeast two‐hybrid assays showed that the ASR proteins can participate in the WMBW (WRKY, MYB, B‐HLH, and WDR) anthocyanin regulatory complex by interacting with the transcription factors AN1 and AN11. All three ASRs can induce anthocyanin synthesis when ectopically expressed in P. hybrida lines, but ASR1 appeared to be the most effective. The expression patterns of ASR1 and ASR2 cover several different petunia tissues with higher expression at early stages of bud development. In contrast, ASR3 is only weakly expressed in the stigma, ovary, and anther filaments. The characterization of these novel ASR MYB genes completes the picture of the MYB members of the petunia anthocyanin regulatory MBW complex and suggests possible mechanisms of the diversification of pigmentation patterns during plant evolution.

Class XI Myosins Contribute to Auxin Response and Senescence-Induced Cell Death in Arabidopsis.

The integrity and dynamics of actin cytoskeleton is necessary not only for plant cell architecture but also for membrane trafficking-mediated processes such as polar auxin transport, senescence, and cell death. In Arabidopsis, the inactivation of actin-based molecular motors, class XI myosins, affects the membrane trafficking and integrity of actin cytoskeleton, and thus causes defective plant growth and morphology, altered lifespan and reduced fertility. To evaluate the potential contribution of class XI myosins to the auxin response, senescence and cell death, we followed the flower and leaf development in the triple gene knockout mutant xi1 xi2 xik (3KO) and in rescued line stably expressing myosin XI-K:YFP (3KOR). Assessing the development of primary inflorescence shoots we found that the 3KO plants produced more axillary branches. Exploiting the auxin-dependent reporters DR5::GUS and IAA2::GUS, a significant reduction in auxin responsiveness was found throughout the development of the 3KO plants. Examination of the flower development of the plants stably expressing the auxin transporter PIN1::PIN1-GFP revealed partial loss of PIN1 polarization in developing 3KO pistils. Surprisingly, the stable expression of PIN1::PIN1-GFP significantly enhanced the semi-sterile phenotype of the 3KO plants. Further we investigated the localization of myosin XI-K:YFP in the 3KOR floral organs and revealed its expression pattern in floral primordia, developing pistils, and anther filaments. Interestingly, the XI-K:YFP and PIN1::PIN1-GFP shared partially overlapping but distinct expression patterns throughout floral development. Assessing the foliar development of the 3KO plants revealed increased rosette leaf production with signs of premature yellowing. Symptoms of the premature senescence correlated with massive loss of chlorophyll, increased cell death, early plasmolysis of epidermal cells, and strong up-regulation of the stress-inducible senescence-associated gene SAG13 in 3KO plants. Simultaneously, the reduced auxin responsiveness and premature leaf senescence were accompanied by significant anthocyanin accumulation in 3KO tissues. Collectively, our results provide genetic evidences that Arabidopsis class XI myosins arrange the flower morphogenesis and leaf longevity via contributing to auxin responses, leaf senescence, and cell death.

Unfertilized ovary pushes wheat flower open for cross-pollination.

Bread wheat is strongly autogamous; however, an opportunity for outcrossing occurs when self-pollination fails and florets open. The first phase of floret opening at anthesis is short and induced by lodicule turgidity. Some wheat florets re-open post-anthesis for several days, known as the 'second opening', for which the underlying mechanisms are largely unknown. We performed detailed physiological, anatomical, and histological investigations to understand the biological basis of the flower opening process. Wheat florets were observed open when the ovary was unfertilized. Unfertilized ovaries significantly increased in radial size post-anthesis, pushing the lemma and palea apart to open the florets. The absence of fertile pollen was not directly linked to this, but anther filament elongation coincided with initiation of ovary swelling. The pericarp of unfertilized ovaries did not undergo degeneration as normally seen in developing grains, instead pericarp cells remained intact and enlarged, leading to increased ovary radial size. This is a novel role for the ovary pericarp in wheat flower opening, and the knowledge is useful for facilitating cross-pollination in hybrid breeding. Ovary swelling may represent a survival mechanism in autogamous cereals such as wheat and barley, ensuring seed set in the absence of self-fertilization and increasing genetic diversity through cross-pollination.

A novel role of the soybean clock gene LUX ARRHYTHMO in male reproductive development

The evening complex of ELF4-ELF3-LUX proteins is an integral component of a plant circadian clock. LUX ARRHYTHMO (LUX) is one of the key components of the evening complex, and that play a key role in circadian rhythms and flowering. Here, we report that diverged soybean LUX has the additional role in male reproductive development. We studied diurnal and circadian rhythms of soybean LUX (GmLUXa, GmLUXb, and GmLUXc) using qRT-PCR, and show its nuclear localisation by particle bombardment. Yeast-two hybrid (Y2H) studies indicate that both GmLUXb and GmLUXc form an evening complex with GmELF4b and GmELF3a, respectively. Ectopic expression of GmLUXb in Arabidopsis lux mutants can complement functions of AtLUX, whereas GmLUXc generates novel phenotypes of serrated leaves, stunted plants, shortened anther filament, and low seed set. Overall, our results suggest that the LUX gene has diverged in soybean where GmLUXb and GmLUXc share the role to control flowering time, but GmLUXc has evolved to regulate anther filament growth and seed set by regulating the Gibberellin hormone biosynthesis pathway.

Watsonia palustris (Iridaceae), a new species from KwaZulu-Natal, South Africa and a revised key to allied summer rainfall species

Watsonia palustris is a wetland species restricted to marshy grassland in the vicinity of Greytown in central KwaZulu-Natal. Belonging to a group of species of eastern South Africa, Lesotho and Swaziland with pink flowers and a funnel-shaped perianth tube, it is characterized by its clumped habit, very narrow leaves, late summer flowering, partly herbaceous floral bracts, and shortly exserted anther filaments. Watsonia now comprises 53 species of corm-bearing geophytes restricted to southern Africa.

The VviMYB80 Gene is Abnormally Expressed in Vitis vinifera L. cv. 'Zhong Shan Hong' and its Expression in Tobacco Driven by the 35S Promoter Causes Male Sterility.

Anther development is a very precise and complicated process. In Arabidopsis, the AtMYB80 transcription factor regulates genes involved in pollen development and controls the timing of tapetal programmed cell death (PCD). In this study, we isolated and characterized cDNA for VviMYB80 expressed in flower buds of male-sterile Vitis vinifera L. cv. 'Zhong Shan Hong', a late-maturing cultivar derived from self-progeny of cv. 'Wink'. VviMYB80 belongs to the MYB80 subfamily and clusters with AtMYB35/TDF1 in a distinct clade. We found that in flower buds, expression of the VviMYB80 gene in cv. 'Zhong Shan Hong' sharply increased at the tetrad stage, resulting in a higher and earlier transcript level than that found in cv. 'Wink'. Expression of the VviMYB80 gene, driven by the 35S promoter, caused pleiotropic effects on the stamens, including smaller and shriveled anthers, delayed dehiscence, fewer seeds, shorter anther filaments, distorted pollen shape and a lack of cytoplasm, with the tapetum exhibiting hypertrophy in transformed tobacco. These results suggest that VviMYB80 may play an important role in stamen development and that expression of VviMYB80 driven by the 35S promoter in tobacco induces male sterility.