Detection of Reproducible Major Effect QTL for Petal Traits in Garden Roses

The detection of QTL by association genetics depends on the genetic architecture of the trait under study, the size and structure of the investigated population and the availability of phenotypic and marker data of sufficient quality and quantity. In roses, we previously demonstrated that major QTL could already be detected in small association panels. In this study, we analyzed petal number, petal size and fragrance in a small panel of 95 mostly tetraploid garden rose genotypes. After genotyping the panel with the 68 K Axiom WagRhSNP chip we detected major QTL for all three traits. Each trait was significantly influenced by several genomic regions. Some of the QTL span genomic regions that comprise several candidate genes. Selected markers from some of these regions were converted into KASP markers and were validated in independent populations of up to 282 garden rose genotypes. These markers demonstrate the robustness of the detected effects independent of the set of genotypes analyzed. Furthermore, the markers can serve as tools for marker-assisted breeding in garden roses. Over an extended timeframe, they may be used as a starting point for the isolation of the genes underlying the QTL.

Disintegration of Polyalthia debilis (Annonaceae): P. cambodica comb. nov., P. canaensis comb. et stat. nov., and P. suthepensis nom. nov. for Unona dubia

Polyalthia debilis (Annonaceae), a widespread species in Cambodia, Thailand, and Vietnam, is recircumscribed by morphological reappraisal. Three heterotypic synonyms of Polyalthia debilis, viz. Popowia cambodica, Popowia cambodica var. canaensis, and Unona dubia differ from Polyalthia debilis and from each other by different combinations of the following traits: plant height, leaf blade size, petiole length, flowering pedicel length, inner and outer petal size, number of carpels per flower, number of ovules per ovary, and stipe length. Consequently, each heterotypic synonym deserves recognition as a separate species. Polyalthia cambodica comb. nov. and Polyalthia canaensis comb. et stat. nov. are accordingly made; and Polyalthia suthepensis, a replacement name for Unona dubia, is proposed because the name Polyalthia dubia pre-exists. A key to Polyalthia debilis, Polyalthia cambodica, Polyalthia canaensis, and Polyalthia suthepensis is provided.

Intraspecific relationships between floral signals and rewards with implications for plant fitness

Within-species variation in traits such as petal size or color often provides reliable information to pollinators about the rewards offered to them by flowers. In spite of potential disadvantages of allowing pollinators to discriminate against less-rewarding flowers, examples of informative floral signals are diverse in form and widely distributed across plant taxa, apparently having evolved repeatedly in different lineages. Although hypotheses about the adaptive value of providing reward information have been proposed and tested in a few cases, a unified effort to understand the evolutionary mechanisms favoring informative floral signals has yet to emerge. This review describes the diversity of ways in which floral signals can be linked with floral rewards within plant species and discusses the constraints and selective pressures on floral signal-reward relationships. It focuses particularly on how information about floral rewards can influence pollinator behavior and how those behavioral changes may, in turn, affect plant fitness, selecting either for providing or withholding reward information. Most of the hypotheses about the evolution of floral signal-reward relationships are, as yet, untested, and the review identifies promising research directions for addressing these considerable gaps in knowledge. The advantages and disadvantages of sharing floral reward information with pollinators likely play an important role in floral trait evolution, and opportunities abound to further our understanding of this neglected aspect of floral signaling.

The genetic control of leaf and petal allometric variations in Arabidopsis thaliana

BackgroundOrgan shape and size covariation (allometry) are essential concepts for the study of evolution and development. Although ample research has been conducted on organ shape and size, little research has considered the correlated variation of these two traits and quantitatively measured the variation in a common framework. The genetic basis of allometry variation in a single organ or among different organs is also relatively unknown.ResultsA principal component analysis (PCA) of organ landmarks and outlines was conducted and used to quantitatively capture shape and size variation in leaves and petals of multiparent advanced generation intercross (MAGIC) populations of Arabidopsis thaliana. The PCA indicated that size variation was a major component of allometry variation and revealed negatively correlated changes in leaf and petal size. After quantitative trait loci (QTL) mapping, five QTLs for the fourth leaf, 11 QTLs for the seventh leaf, and 12 QTLs for petal size and shape were identified. These QTLs were not identical to those previously identified, with the exception of the ER locus. The allometry model was also used to measure the leaf and petal allometry covariation to investigate the evolution and genetic coordination between homologous organs. In total, 12 QTLs were identified in association with the fourth leaf and petal allometry covariation, and eight QTLs were identified to be associated with the seventh leaf and petal allometry covariation. In these QTL confidence regions, there were important genes associated with cell proliferation and expansion with alleles unique to the maximal effects accession. In addition, the QTLs associated with life-history traits, such as days to bolting, stem length, and rosette leaf number, which were highly coordinated with climate change and local adaption, were QTL mapped and showed an overlap with leaf and petal allometry, which explained the genetic basis for their correlation.ConclusionsThis study explored the genetic basis for leaf and petal allometry and their interaction, which may provide important information for investigating the correlated variation and evolution of organ shape and size in Arabidopsis.

The genetic control of leaf and petal allometric variations in Arabidopsis thaliana

Background Organ shape and size covariation (allometry) factors are essential concepts for the study of evolution and development. Although ample research has been conducted on organ shape and size, little research has considered the correlated variation of these two traits and quantitatively measured the variation in a common framework. The genetic basis of allometry variation in a single organ or among different organs is also relatively unknown. Results A principal component analysis (PCA) of organ landmarks and outlines was conducted and used to quantitatively capture shape and size variation in leaves and petals of multiparent advanced generation intercross (MAGIC) populations of Arabidopsis thaliana. The PCA indicated that size variation was a major component of allometry variation and revealed negatively correlated changes in leaf and petal size. After quantitative trait loci (QTL) mapping, five QTLs for the fourth leaf, 11 QTLs for the seventh leaf, and 12 QTLs for petal size and shape were identified. These QTLs were not identical to those previously identified, with the exception of the ER locus. The allometry model was also used to measure the leaf and petal allometry covariation to investigate the evolution and genetic coordination between homologous organs. In total, 12 QTLs were identified in association with the fourth leaf and petal allometry covariation, and eight QTLs were identified to be associated with the seventh leaf and petal allometry covariation. In these QTL confidence regions, there were important genes associated with cell proliferation and expansion with alleles unique to the maximal effects accession. In addition, the QTLs associated with life-history traits, such as days to bolting, stem length, and rosette leaf number, which were highly coordinated with climate change and local adaption, were QTL mapped and showed an overlap with leaf and petal allometry, which explained the genetic basis for their correlation. Conclusions This study explored the genetic basis for leaf and petal allometry and their interaction, which may provide important information for investigating the correlated variation and evolution of organ shape and size in Arabidopsis.

The genetic control of leaf and petal allometric variations in Arabidopsis thaliana

Background Organ shape and size covariation (allometry) are essential concepts for the study of evolution and development. Although ample research has been conducted on organ shape and size, little research has considered the correlated variation of these two traits and quantitatively measured the variation in a common framework. The genetic basis of allometry variation in a single organ or among different organs is also relatively unknown.Results A principal component analysis (PCA) of organ landmarks and outlines was conducted and used to quantitatively capture shape and size variation in leaves and petals of multiparent advanced generation intercross (MAGIC) populations of Arabidopsis thaliana. The PCA indicated that size variation was a major component of allometry variation and revealed negatively correlated changes in leaf and petal size. After quantitative trait loci (QTL) mapping, five QTLs for the fourth leaf, 11 QTLs for the seventh leaf, and 12 QTLs for petal size and shape were identified. These QTLs were not identical to those previously identified, with the exception of the ER locus. The allometry model was also used to measure the leaf and petal allometry covariation to investigate the evolution and genetic coordination between homologous organs. In total, 12 QTLs were identified in association with the fourth leaf and petal allometry covariation, and eight QTLs were identified to be associated with the seventh leaf and petal allometry covariation. In these QTL confidence regions, there were important genes associated with cell proliferation and expansion with alleles unique to the maximal effects accession. In addition, the QTLs associated with life-history traits, such as days to bolting, stem length, and rosette leaf number, which were highly coordinated with climate change and local adaption, were QTL mapped and showed an overlap with leaf and petal allometry, which explained the genetic basis for their correlation.Conclusions This study explored the genetic basis for leaf and petal allometry and their interaction, which may provide important information for investigating the correlated variation and evolution of organ shape and size in Arabidopsis.

The genetic control of leaf and petal allometric variations in Arabidopsis thaliana

Background Organ shape and size co-variation (allometry) is an essential concept for the study of evolution and development. Although ample research has been conducted on organ shape and size, little of it has considered the correlated variation of these two traits and quantitatively measured the variation in a common framework. The genetic basis of allometry variation in a single organ or among different organs is also relatively unknown. Results A principal component analysis (PCA) of organ landmarks and outlines was conducted and used to quantitatively capture shape and size variation in leaves and petals of multiparent advanced generation intercross (MAGIC) populations of Arabidopsis thaliana . PCA indicated that size variation was a major component of allometry variation and revealed negatively correlated changes in leaf and petal size. After QTL mapping, five QTLs for the fourth leaf, 11 QTLs for the seventh leaf, and 12 QTLs for the petal size and shape were identified. These QTLs were not identical to those previously identified, with the exception of the ER locus. The allometry model was also used to measure the leaf and petal allometry covariation to investigate the evolution and genetic coordination between homologous organs. Totally, 12 QTLs were identified in association with the fourth leaf and petal allometry covariation, and eight QTLs were identified to associate with the seventh leaf and petal allometry covariation. In these QTL confidence regions, there were important genes associated with cell proliferation and expansion with alleles unique to the maximal effects accession. Besides that, the QTLs associated with life-history traits, such as days to bolting, stem length, and rosette leaf number, which was highly coordinated with climate change and local adaption, were QTL mapped and showed an overlap with leaf and petal allometry, which explained the genetic basis for their correlation. Conclusions This study explored the genetic basis for leaf and petal allometry and their interaction, which may provide important information for investigating the organ shape and size correlated variation and evolution in Arabidopsis .

The non-monophyly of Dasymaschalon dasymaschalum (Annonaceae) revealed by a plastid DNA phylogeny, with D. halabalanum sp. nov. from Thailand and D. argenteum comb. nov.

An extended molecular phylogeny of the genus Dasymaschalon (Annonaceae) has been reconstructed using up to six plastid DNA regions (matK, ndhF, rbcL exons; trnL intron; psbA-trnH, trnL-trnF intergenic spacers). The results unraveled the non-monophyly of a widely distributed D. dasymaschalum. A lineage of D. dasymaschalum native to Java and cultivated at Bogor Botanical Garden represents the true D. dasymaschalum, whereas the name Pelticalyx argentea is applicable to a distantly related clade of D. dasymaschalum from mainland Asia. Dasymaschalon argenteum comb. nov. is accordingly made. Additionally, the true D. dasymaschalum has been retrieved as the sister group of D. halabalanum, a new species from Narathiwat Province, southern Thailand herein described. Pedicel length, petal size and color, and the number of stamens per flower principally distinguish the new species from its sister group.

Haplophyllum ermenekense (Rutaceae), a new species from Turkey

A new species ofHaplophyllum,Haplophyllumermenekense(Rutaceae) is described and illustrated in line drawing. It grows on stony slopes of Ermenek town, Karaman province, in southern Turkey. It is compared with the closely related speciesH.myrtifolium.H.ermenekenseis distinguished from the morphologically similarH myrtifoliumchiefly by sepal shape, petal size, capsule size, presence of capsule hair and appendage form. On the other hand, the seed coat and pollen grains surface ofH.ermenekenseandH.myrtifoliumare demonstrated in SEM photographs. In addition to the detailed description, the illustration, distribution map, conservation status and ecology of the new species are also provided.