Virtually all land plants are coated in a cuticle, a waxy polyester that prevents nonstomatal water loss and is important for heat and drought tolerance. Here, we describe a likely genetic basis for ...a divergence in cuticular wax chemistry between
, a drought tolerant crop widely cultivated in hot climates, and its close relative
(maize). Combining chemical analyses, heterologous expression, and comparative genomics, we reveal that: 1) sorghum and maize leaf waxes are similar at the juvenile stage but, after the juvenile-to-adult transition, sorghum leaf waxes are rich in triterpenoids that are absent from maize; 2) biosynthesis of the majority of sorghum leaf triterpenoids is mediated by a gene that maize and sorghum both inherited from a common ancestor but that is only functionally maintained in sorghum; and 3) sorghum leaf triterpenoids accumulate in a spatial pattern that was previously shown to strengthen the cuticle and decrease water loss at high temperatures. These findings uncover the possibility for resurrection of a cuticular triterpenoid-synthesizing gene in maize that could create a more heat-tolerant water barrier on the plant's leaf surfaces. They also provide a fundamental understanding of sorghum leaf waxes that will inform efforts to divert surface carbon to intracellular storage for bioenergy and bioproduct innovations.
O sorgo sacarino vem ganhando destaque no cenário agrícola brasileiro, por se tratar de uma espécie de características agronômicas, semelhantes a cana de açúcar, se destacando, pelo menor tempo de ...cultivo, e resistências a fatores bióticos e abióticos, que impossibilitam o cultivo da cana. Objetivando determinar cultivares de sorgo sacarino, que demonstram adaptabilidade nas condições edafoclimáticas do município de Confresa- MT, o presente estudo, avaliou 23 híbridos experimentais do Programa de Melhoramento da Embrapa Milho e Sorgo. O trabalho foi desenvolvido com delineamento experimental em látice triplo, analisando características como altura de plantas, diâmetro do colmo, número de colmos, peso de massa verde, resistência ao acamamento, peso de colmo, volume de caldo, sólidos solúveis totais, número de panículas e período de maturação (ciclo). Houve variabilidade genética para todas as características exceto número de colmos. Foi observado uma relação positiva entre a variável diâmetro de colmo e altura de plantas, para o acúmulo de biomassa, e volume de caldo. As cultivares CMSXS5040, e CMSXS5042 apresentaram desempenho satisfatório para cultivo na região.
O sorgo biomassa tem se mostrado uma cultura muito atrativa, por ser pouco exigente em fertilidade, possibilitar um cultivo totalmente mecanizável, e possuir um alto potencial produtivo de massa ...verde. Afim de verificar adaptabilidade ao município de Confresa-MT, este trabalho analisou 19 híbridos experimentais de sorgo biomassa, do Programa de Melhoramento da Embrapa Milho e Sorgo, e uma cultivar comercial (AGRI002E). O delineamento experimental utilizado foi em blocos casualizados, com 3 repetições. Os parâmetros analisados foram diâmetro de colmos na altura do peito (DAP), altura de planta (ALT), resistência de plantas ao acamamento (RA), produtividade de massa verde (PMV), número de colmos (NC), peso médio de panícula (PP), número de panículas (NP), e ciclo. Foi verificado que cultivares mais produtivas apresentaram em sua maioria altura e diâmetro maiores, além de maior resistência ao acamamento e ciclos mais tardios, como por exemplo a CMSXS7501, CMSXS7515 e AGRI002E, que se destacaram nestas variáveis em relação as demais cultivares, com produtividades acima de 140 t. ha-1. No entanto a CMSXS7509 se destaca das demais, por se caracterizar como uma cultivar com produtividade expressiva, mas apresentar ciclo curto (140 dias).
A cultura do sorgo forrageiro vem apresentando um enorme crescimento nos últimos anos, devido ao grande potencial produtivo e forrageiro. Paralelo ao seu crescimento há também um aumento na demanda ...por herbicidas que viabilizam sua produção. Neste sentido, objetivou-se avaliar a eficiência do uso de herbicidas no controle de plantas daninhas e sua influência nas características de crescimento e produção do sorgo forrageiro. O experimento foi conduzido em delineamento de blocos casualizados, com 4 repetições e 9 tratamentos Testemunha; Capinado; 2,4-D (100%); 2,4-D (150%); Pendimetalina (100%); Pendimetalina (150%); 2,4-D (100%) + Pendimetalina (150%); 2,4-D (150%) + Pendimetalina (100%); 2,4-D (150%) + Pendimetalina (150%) aplicados aos 15 dias após a semeadura. Foram analisadas as seguintes variáveis: altura de plantas, diâmetro do caule, número de folhas, controle de plantas daninhas, fitotoxidade e produtividade. Os dados foram submetidos a análise de variância usando o software Sisvar. Para os dados qualitativos, utilizou-se o teste de Scott-Knott a 5% de probabilidade e para os dados quantitativos, regressão polinomial. O uso dos herbicidas isolados ou em associação, influenciou nas variáveis produtivas da cultura do sorgo. Os herbicidas 2,4-D (100%) e Pendimetalina (100%) se mostraram com potencial para utilização na cultura do sorgo.
Over evolutionary time, plants have developed sophisticated regulatory mechanisms to adapt to fluctuating nitrogen (N) environments, ensuring that their growth is balanced with their responses to N ...stress. This study explored the potential of L-tryptophan (Trp) in regulating sorghum root growth under conditions of N limitation. Here, two distinct sorghum genotypes (low-N tolerance 398B and low-N sensitive CS3541) were utilized for investigating effect of low-N stress on root morphology and conducting a comparative transcriptomics analysis. Our foundings indicated that 398B exhibited longer roots, greater root dry weights, and a higher Trp content compared to CS3541 under low-N conditions. Furthermore, transcriptome analysis revealed substantial differences in gene expression profiles related to Trp pathway and carbon (C) and N metabolism pathways between the two genotypes. Additional experiments were conducted to assess the effects of exogenous Trp treatment on the interplay between sorghum root growth and low-N tolerance. Our observations showed that Trp-treated plants developed longer root and had elevated levels of Trp and IAA under low-N conditons. Concurrently, these plants demonstrated stronger physiological activities in C and N metabolism when subjected to low-N stress. These results underscored the pivotal role of Trp on root growth and low-N stress responses by balancing IAA levels and C and N metabolism. This study not only deepens our understanding of how plants maintain growth plasticity during environmental stress but also provides valuable insights into the availability of amino acid in crops, which could be instrumental in developing strategies for promoting crop resilience to N deficiency.
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•Low N stress increases sorghum root growth and Trp content.•Low N upregulates the expression of Trp genes related to the IAA synthesis and signal transduction pathway.•Low N downregulates the expression of C and N metabolism genes except for alpha-amylase genes.•Trp serves as a key coordinator of root growth and low N stress responses by balancing IAA and C and N metabolism.
Highlight Photorespiratory genes are expressed tissue-specific in the leaves of the C sub(4) grass Sorghum bicolor. Most but not all of them are confined to the bundle sheath cells.One of the ...hallmarks of C sub(4) plants is the division of labor between two different photosynthetic cell types, the mesophyll and the bundle sheath cells. C sub(4) plants are of polyphyletic origin and, during the evolution of C sub(4) photosynthesis, the expression of thousands of genes was altered and many genes acquired a cell type-specific or preferential expression pattern. Several lines of evidence, including computational modeling and physiological and phylogenetic analyses, indicate that alterations in the expression of a key photorespiration-related gene, encoding the glycine decarboxylase P subunit, was an early and important step during C sub(4) evolution. Restricting the expression of this gene to the bundle sheath led to the establishment of a photorespiratory CO sub(2) pump. We were interested in whether the expression of genes related to photorespiration remains bundle sheath specific in a fully optimized C sub(4) species. Therefore we analyzed the expression of photorespiratory and C sub(4) cycle genes using RNA in situ hybridization and transcriptome analysis of isolated mesophyll and bundle sheath cells in the C sub(4) grass Sorghum bicolor. It turns out that the C sub(4) metabolism of Sorghum is based solely on the NADP-dependent malic enzyme pathway. The majority of photorespiratory gene expression, with some important exceptions, is restricted to the bundle sheath.
The process of crop domestication often consists of two stages: initial domestication, where the wild species is first cultivated by humans, followed by diversification, when the domesticated species ...are subsequently adapted to more environments and specialized uses. Selective pressure to increase sugar accumulation in certain varieties of the cereal crop Sorghum bicolor is an excellent example of the latter; this has resulted in pronounced phenotypic divergence between sweet and grain-type sorghums, but the genetic mechanisms underlying these differences remain poorly understood.
Here we present a new reference genome based on an archetypal sweet sorghum line and compare it to the current grain sorghum reference, revealing a high rate of nonsynonymous and potential loss of function mutations, but few changes in gene content or overall genome structure. We also use comparative transcriptomics to highlight changes in gene expression correlated with high stalk sugar content and show that changes in the activity and possibly localization of transporters, along with the timing of sugar metabolism play a critical role in the sweet phenotype.
The high level of genomic similarity between sweet and grain sorghum reflects their historical relatedness, rather than their current phenotypic differences, but we find key changes in signaling molecules and transcriptional regulators that represent new candidates for understanding and improving sugar metabolism in this important crop.
Sorghum (Sorghum bicolor) roots release biological nitrification inhibitors (BNIs) to suppress soil nitrification. Presence of NH sub(4) super(+) in the rhizosphere stimulates BNIs release and it is ...hypothesized to be functionally associated with plasma membrane (PM) H super(+)-ATPase activity. However, whether the H super(+)-ATPase is regulated at the transcriptional level, and if so, which isoforms of the H super(+)-ATPases are involved in BNIs release are not known. Also, it is not clear whether the stimulation on BNIs release from roots is due to NH sub(4) super(+) uptake or its assimilation, which are addressed in this study. Root exudates from intact sorghum plants were collected using aerated solutions of NH sub(4) super(+) or methyl-ammonium (MeA); and the BNI-activity release was determined. PM vesicles were isolated from fresh roots using a two-phase partitioning system; and the hydrolytic H super(+)-ATPase activity was determined. All genes encoding PM H super(+)-ATPases were searched in sorghum genome, and their expression in response to NH sub(4) super(+) or MeA were analyzed by quantitative RT-PCR in sorghum roots. BNIs release and PM H super(+)-ATPase activity increased with NH sub(4) super(+) concentration ( less than or equal to 1.0 mM) in the root-exudate collection solutions, but at higher concentrations, it did not respond further or declined in case of the PM H super(+)-ATPase activity. Twelve PM H super(+)-ATPase genes were identified in sorghum genome; and these isoforms were designated SbA1 to SbA12. Five H super(+)-ATPase genes were stimulated by NH sub(4) super(+) in the rhizosphere, and have similar expression pattern, which is consistent with the variation in H super(+)-ATPase activity. MeA, a non-metabolizable analogue of NH sub(4) super(+), had no significant effects on BNIs release, H super(+)-ATPase activity, or expression of the H super(+)-ATPase genes. Our results suggest that the functional link between PM H super(+)-ATPase activity and BNIs release is evident only at NH sub(4) super(+) levels of less than or equal to 1.0 mM in the rhizosphere. The variation in PM H super(+)-ATPase activity by NH sub(4) super(+) is due to transcriptional regulation of five isoforms of the H super(+)-ATPases. The stimulatory effect of NH sub(4) super(+) on BNIs release is functionally associated with NH sub(4) super(+) assimilation and not just with NH sub(4) super(+) uptake alone.
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