Structure, expression and function analysis of class I KNOX genes in Populus.

Knotted-like homeobox (knox) genes constitute a gene family in plants. Class I knox genes are expressed in shoot apical meristems, and (with notable exceptions) not in lateral organ primordia. Class II genes have more diverse expression patterns. Loss and gain of function mutations indicate that knox genes are important regulators of meristem function. Gene duplication has contributed to the evolution of families of homeodomain proteins in metazoans. We believe that similar mechanisms have contributed to the diversity of knox gene function in plants. Knox genes may have contributed to the evolution of compound leaves in tomato and could be involved in the evolution of morphological traits in other species. Alterations in cis-regulatory regions in some knox genes correlate with novel patterns of gene expression and distinctive morphologies. Preliminary data from the analysis of class I knox gene expression illustrates the evolution of complex patterns of knox expression is likely to have occurred through loss and gain of domains of gene expression.

Decision letter: Gamete expression of TALE class HD genes activates the diploid sporophyte program in Marchantia polymorpha

Time to Step Up to the Plate: Adopting the WHO 2006 Growth Curves for US Infants

KNOX genes are indispensable elements of indeterminate apical growth programmes of vascular plant sporophytes. Since little is known about the roles of such genes in non-vascular plants, functional analysis of moss KNOX homologues (MKN genes) was undertaken using the genetically amenable model plant, Physcomitrella patens. Three MKN genes were inactivated by targeted gene knockout to produce single, double and triple mutants. MKN2 (a class 1 KNOX gene) mutants were characterised by premature sporogenesis, abnormal sporophyte ontogeny and irregular spore development. MKN4 (a second class 1 gene) mutants were phenotypically normal. MKN1-3 (a class 2 KNOX gene) mutants exhibited defects in spore coat morphology. Analysis of double and triple mutants revealed that the abnormal sporophytic phenotype of MKN2 mutants was accentuated by mutating MKN4 and to a lesser degree by mutating MKN1-3. The aberrant spore phenotype of MKN1-3 and MKN2 mutants was exacerbated by mutating MKN4. This study provides the first instance in which an abnormal phenotype has been associated with the disruption of a class 2 KNOX gene as well as the first demonstrated case of functional redundancy between a class 1 and a class 2 KNOX gene. We conclude that KNOX genes play significant roles in programming sporophytic development in moss and we provide evidence that ancestral function(s) of this gene family were instrumental in the successful transition of plants to a terrestrial environment.

A major leaf shape locus (L) was mapped with molecular markers and genomically targeted to a small region in the D-genome of cotton. By using expression analysis and candidate gene mapping, two LMI1 -like genes are identified as possible candidates for leaf shape trait in cotton. Leaf shape in cotton is an important trait that influences yield, flowering rates, disease resistance, lint trash, and the efficacy of foliar chemical application. The leaves of okra leaf cotton display a significantly enhanced lobing pattern, as well as ectopic outgrowths along the lobe margins when compared with normal leaf cotton. These phenotypes are the hallmark characteristics of mutations in various known modifiers of leaf shape that culminate in the mis/over-expression of Class I KNOX genes. To better understand the molecular and genetic processes underlying leaf shape in cotton, a normal leaf accession (PI607650) was crossed to an okra leaf breeding line (NC05AZ21). An F2 population of 236 individuals confirmed the incompletely dominant single gene nature of the okra leaf shape trait in Gossypium hirsutum L. Molecular mapping with simple sequence repeat markers localized the leaf shape gene to 5.4 cM interval in the distal region of the short arm of chromosome 15. Orthologous mapping of the closely linked markers with the sequenced diploid D-genome (Gossypium raimondii) tentatively resolved the leaf shape locus to a small genomic region. RT-PCR-based expression analysis and candidate gene mapping indicated that the okra leaf shape gene (L (o) ) in cotton might be an upstream regulator of Class I KNOX genes. The linked molecular markers and delineated genomic region in the sequenced diploid D-genome will assist in the future high-resolution mapping and map-based cloning of the leaf shape gene in cotton.

The KNOX gene family codes for transcriptional regulators with a variety of functions in plant developmental and physiological processes. In this study, a genome-wide comparative analysis of KNOX genes in Poplar (Populustrichocarpa) and rice (Oryza sativa L. ssp. japonica) was carried out. With comprehensive computational analyses, which take into account the gene structures, phylogeny and conserved motifs, 15 and 13 KNOX genes in Poplar and rice were identified, respectively. These KNOX genes were further divided into 3 groups. The Poplar gene POPTR_0012s04040 and the rice genes LOC_Os03g47042 and LOC_Os03g47022 were classified to a new group of KNOX genes without ahomeobox domain together with KNATM, which were proposed to play potential role in plant development and pluripotency. The identification of KNATM homolog in monocotyledons (rice) provided a strong support for proposing an ancient shuffling of HOMEOBOX gene with MEINOX gene took place in the KNOX phylogeny. Using subcellular location information, GO (gene ontology) and expression profile analysis, KNOX genes in rice and poplar were proposed to function similarly to the members in Arabidopsis. Our observations may lay the foundation for future functional analysis of KNOX genes in rice and poplar to unravel their biological roles in cellular pluripotency.

Bulbil formation in Agave tequilana was analysed with the objective of understanding this phenomenon at the molecular and cellular levels. Bulbils formed 14-45 d after induction and were associated with rearrangements in tissue structure and accelerated cell multiplication. Changes at the cellular level during bulbil development were documented by histological analysis. In addition, several cDNA libraries produced from different stages of bulbil development were generated and partially sequenced. Sequence analysis led to the identification of candidate genes potentially involved in the initiation and development of bulbils in Agave, including two putative class I KNOX genes. Real-time reverse transcription-PCR and in situ hybridization revealed that expression of the putative Agave KNOXI genes occurs at bulbil initiation and specifically in tissue where meristems will develop. Functional analysis of Agave KNOXI genes in Arabidopsis thaliana showed the characteristic lobed phenotype of KNOXI ectopic expression in leaves, although a slightly different phenotype was observed for each of the two Agave genes. An Arabidopsis KNOXI (knat1) mutant line (CS30) was successfully complemented with one of the Agave KNOX genes and partially complemented by the other. Analysis of the expression of the endogenous Arabidopsis genes KNAT1, KNAT6, and AS1 in the transformed lines ectopically expressing or complemented by the Agave KNOX genes again showed different regulatory patterns for each Agave gene. These results show that Agave KNOX genes are functionally similar to class I KNOX genes and suggest that spatial and temporal control of their expression is essential during bulbil formation in A. tequilana.

Introduction to the Special Issue on Class Dynamics from Socialism to Post-Socialism

KNOXs, a type of homeobox genes that encode atypical homeobox proteins, play an essential role in the regulation of growth and development, hormonal response, and abiotic stress in plants. However, the KNOX gene family has not been explored in sweet potato. In this study, through sequence alignment, genomic structure analysis, and phylogenetic characterization, 17, 12 and 11 KNOXs in sweet potato (I. batatas, 2n = 6x = 90) and its two diploid relatives I. trifida (2n = 2x = 30) and I. triloba (2n = 2x = 30) were identified. The protein physicochemical properties, chromosome localization, phylogenetic relationships, gene structure, protein interaction network, cis-elements of promoters, tissue-specific expression and expression patterns under hormone treatment and abiotic stresses of these 40 KNOX genes were systematically studied. IbKNOX4, -5, and − 6 were highly expressed in the leaves of the high-yield varieties Longshu9 and Xushu18. IbKNOX3 and IbKNOX8 in Class I were upregulated in initial storage roots compared to fibrous roots. IbKNOXs in Class M were specifically expressed in the stem tip and hardly expressed in other tissues. Moreover, IbKNOX2 and − 6, and their homologous genes were induced by PEG/mannitol and NaCl treatments. The results showed that KNOXs were involved in regulating growth and development, hormone crosstalk and abiotic stress responses between sweet potato and its two diploid relatives. This study provides a comparison of these KNOX genes in sweet potato and its two diploid relatives and a theoretical basis for functional studies.

Objectives: To analyse the variability in health status within as well as between socioeconomic groups. What is the range of individual variability in the health effects of socioeconomic status? Is...

Occupational social class has become a leading indicator of social inequalities in health. In the US, economic sectors are distinct with respect to wages, benefits, job security, promotion ladders and working conditions. The growing economic sector of self-employed workers is characterized by lower wages and benefits, and greater job insecurity. Little attention has been given to the association between economic sector measures of social class and all-cause mortality, and there have been no studies of mortality among the self-employed. To determine risk of death associated with economic sector social class, this study entails a longitudinal analysis of the National Health Interview Survey (NHIS), an annual household survey representative of the US population for the period 1986-1994 (n = 377,129). The sample includes 201,566 men and 175,563 women, aged 24-65 years of age, in the civilian labor force. Non- professionals are at higher risk of death than professionals across all sectors and self-employed professionals are at higher risk of death than professionals employed in government and production. Additional social class differences are accounted for by age, race, gender and marital status. Results are also partially explained by income. After controlling for income, Black professionals did not show a lower risk of death than Black non-professionals and self-employed Hispanic professionals had a higher risk of death than Hispanic professionals employed in the private sector. Given the growth of self-employment in the US, the noted increased risk of death among self-employed professionals merits further investigation and monitoring.

KxhKN5 (class 1 KNOX gene) was cloned from Kalanchoe×houghtonii with strong tendency to form epiphylls on leaves. KxhKN5 appear to be homologue of BP of A. thaliana on the basis of phylogeny, expression and phenotype analysis. Beside the modification of several plant and leaf traits, the appearance of epiphylls was drastically reduced by both the silencing and the over-expression of KxhKN5 in most of the generated clones. In silenced clones, epiphyll production followed the morphogenetic pathway of the WT plants: somatic embryos outbreak in the centre of each leaf-pedestal, grown in the notch between leaf indentations and were supported by a suspensor. The connection between the epiphyll and the mother plant did not include any vasculature and as a result, the epiphylls dropped easily from the mother plant. The most represented category of over expressor clones, disclosed a novel pattern of epiphyll development: the leaf-pedestals were absent and single bud outbreaks in each leaf notch. Buds developed into shoots which remained attached to the maternal plant by a strong vascular connection. The leaves supporting shoots, produced a thickened midrib and veins, and their lamina ceased expanding. Finally, the leaf/shoot structure resembles a lateral branch. The ectopic expression of KxhKN5 in K.×houghtonii induces a process comparable to the alternation of leaf and shoot formation in other species and support the idea, that it is the variation in shared molecular and developmental processes which produces the growth of specific structures.

BackgroundThe COVID-19 pandemic has required clinicians to pivot to offering services via telehealth; however, it is unclear which patients (users of care) are equipped to use digital health. This is especially pertinent for adults managing chronic diseases, such as obesity, hypertension, and diabetes, which require regular follow-up, medication management, and self-monitoring.ObjectiveThe aim of this study is to measure the trends and assess factors affecting health information technology (HIT) use among members of the US population with and without cardiovascular risk factors.MethodsWe used serial cross-sectional data from the National Health Interview Survey for the years 2012-2018 to assess trends in HIT use among adults, stratified by age and cardiovascular risk factor status. We developed multivariate logistic regression models adjusted for age, sex, race, insurance status, marital status, geographic region, and perceived health status to assess the likelihood of HIT use among patients with and without cardiovascular disease risk factors.ResultsA total of 14,304 (44.6%) and 14,644 (58.7%) participants reported using HIT in 2012 and 2018, respectively. When comparing the rates of HIT use for the years 2012 and 2018, among participants without cardiovascular risk factors, the HIT use proportion increased from 51.1% to 65.8%; among those with one risk factor, it increased from 43.9% to 59%; and among those with more than one risk factor, it increased from 41.3% to 54.7%. Increasing trends in HIT use were highest among adults aged >65 years (annual percentage change [APC] 8.3%), who had more than one cardiovascular risk factor (APC 5%) and among those who did not graduate from high school (APC 8.8%). Likelihood of HIT use was significantly higher in individuals who were younger, female, and non-Hispanic White; had higher education and income; were married; and reported very good or excellent health status. In 2018, college graduates were 7.18 (95% CI 5.86-8.79), 6.25 (95% CI 5.02-7.78), or 7.80 (95% CI 5.87-10.36) times more likely to use HIT compared to adults without high school education among people with multiple cardiovascular risk factors, one cardiovascular risk factor, or no cardiovascular risk factors, respectively.ConclusionsOver 2012-2018, HIT use increased nationally, with greater use noted among younger and higher educated US adults. Targeted strategies are needed to engage wider age, racial, education, and socioeconomic groups by lowering barriers to HIT access and use.

Explanations for racial/ethnic disparities in health are varied and complex. This paper reviews the literature to assess the extent to which current disparities are a consequence of racial differences in the social class composition of the US population. We focus this review on African Americans and examine studies that provide information on the effect of race on four outcome measures: infant mortality, hypertension, substance use, and mortality from all-causes. Twenty-three studies were identified that met criteria for inclusion in this review. As expected, most studies provide evidence that socioeconomic conditions are a major factor explaining racial differences in health. Findings, however, vary for the different health indices. Research in the area of substance abuse provides the most consistent evidence that socioeconomic conditions account for observed racial differences. In contrast, studies on infant mortality and hypertension provide a compelling case that the effects of socioeconomic status are important, but not sufficient to explain racial differences. Evidence on mortality from all-causes is equally divided between studies showing no significant race effect and those in which racial differences persist after adjusting for social class. The paper offers possible explanations for the seemingly divergent results and identifies conceptual and methodologic issues for future research seeking to disentangle the complex relations between race, social class, and health.

Background: Prior studies analyzing the effect of infection and cardiovascular events have met with contradictory results. We investigated whether infectious burden increases cardiovascular mortality in a cross sectional US population. Methods: The public dataset of the National Health and Nutrition Examination Survey III (NHANES III) between the years 1988-1994 was used for the analysis. We included patients >18 years with data on positive antibodies against Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis E, Herpes simplex virus 1 and 2, Toxoplasma, Varicella, Cytomegalovirus (CMV), Human herpes virus -8 and Toxocara (n= 7,876). These infections were combined to create a total infection burden variable. This variable was split into quartiles. The primary outcome was cardiovascular (CV) mortality. Traditional cardiac risk factors along with C-reactive protein (CRP) and social class (insurance, income and education level) were adjusted for in the multivariable analysis. Results: 431 (5.5%) of cardiovascular deaths were reported with a mean follow up of 14.5 years. On a univariable analysis only positive toxoplasma antibody (HR, 95% CI, p-value) were predictive of CV mortality (1.18.,1.03-1.36, 0.02). Independent predictors of CV mortality in the multivariable model were age, female gender, CRP titers, hypertension, smoking, and diabetes. Social class (insurance, income and education level) and total infection burden, quartiles 2 (p = 0.1), 3 (p = 0.4) and 4 (p = 0.1) were not predictive of CV mortality when keeping quartile 1 as the referent. Conclusion: Our observational study in a large database suggests that presence of antibodies against certain viral and parasitic infections is not associated with increased cardiovascular mortality in a nationally representative cohort.