Cassava is a tropical tuberous root crop, feeding over a billion people globally. However, research on the chemical composition and bioactive effects of cassava leaves remains scarce. Two specific varieties of South China No. 9 (green leaves (G.L.)) and South China No. 20 (purple leaves (P.L.)) were investigated in this study. The components of G.L. and P.L. were analyzed under different extraction methods using ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC-Q-TOF/MS). Results showed that cassava leaf extracts are rich in bioactive metabolites such as D-(+)-mannose, trigonelline, rutin, kaempferol-3-O-rutinoside, and oleamide. To assess the anti-inflammatory efficacy of bioactive compounds, animal models were established. Compared to the histamine group (NA), the group treated with the extracts had reduced epidermal thickness in hematoxylin and eosin (HE) staining. Further analysis revealed a drastic reduction in the number of mast cells in toluidine blue (TB) staining and expression levels of inflammatory cytokines (IL-17 and TNF-α) in immunohistochemistry (IHC) staining. The ethanolic extracts from the leaves demonstrated potent anti-inflammatory activities, with the extract from G.L. surpassing that from P.L. Transcriptomic analyses propose that the anti-inflammatory effects of cassava leaves may be related to the modulation of genes involved in mast cell activation, such as Cma1, Cpa3, and Fn1, among others. Network pharmacology unveiled that the extract of cassava leaves modulates pathways associated with apoptosis, inflammation, and metabolism. Molecular docking revealed strong binding interactions between 1-stearoylglycerol and oleamide from cassava leaves extracts and the proteins of AKT1, TNF, and BRAF. Overall, cassava leaf extracts seem to be a promising natural anti-inflammatory agent.

Cassava (Manihot esculenta Crantz) is used as a biomass energy material and an effective supplement for food and feed. Cinnamyl alcohol dehydrogenase (CAD) catalyzes the final step of lignin biosynthesis and is responsible for various stresses. However, systematic investigations of the CAD gene family in cassava have been poorly understood. In this study, a genome-wide survey and bioinformatics analysis of CAD gene family was performed, transcriptomics, qRT-PCR, gene silencing and stress of yeast cell were used for excavate and validate the candidate MeCADs gene. 36 MeCADs genes unevenly distributed across 12 chromosomes were identified. Through phylogenetic analyses alongside their Arabidopsis counterparts, these MeCADs were divided into four groups, each containing a similar structure and conserved motifs. Interestingly, transcriptome data analysis revealed that 32 MeCAD genes were involved in the postharvest physiological deterioration (PPD) process, whereas 27 MeCAD genes showed significant changes. Additionally, the relative quantitative analysis of 6 MeCAD genes demonstrated that they were sensitive to PPD, suggesting that they may be involved in the regulation of PPD. Silencing MeCAD13 and MeCAD28 further showed that lignin content significantly decreased in the leaves. The wound-stress tolerance of transgenic yeast cells was enhanced after transformation with MeCAD13 and MeCAD28. MeCAD13 and MeCAD28 may play positive roles in lignin biosynthesis and PPD response, respectively. These results provided a systematic functional analysis of MeCADs in cassava and paved a new way to genetically modify lignin biosynthesis and PPD tolerance.

木薯原产热带美洲,是世界热区重要的粮食作物,也是世界近十亿人的食粮.然而木薯基因组高度杂合、后代分离严重,定向选育难度大、育种周期长,这些因素严重制约着木薯产业的发展.因此,缩短育种周期、定向选育出木薯优良品种是当今育种工作的重点.近年来,随着测序技术的发展以及多组学、基因编辑、遗传转化等核心技术在育种中的应用,木薯育种工作取得了重大突破.本文综述了木薯育种的最新进展,包括木薯种质资源重要农艺性状评价已从传统表型评价发展到表型与基因型的精准评价、木薯参考基因组的组装与注释及关键性状基因资源的发掘、木薯现代育种策略的发展等.此外,本文还讨论了今后木薯育种的研究方向,这将对推动木薯产业发展、服务国家“一带一路”倡议,以及解决世界热区粮食安全和饲料有效供给具有重要意义.

Cassava tuberous root, as a staple food crop and industrial raw material worldwide, is highly sensitive to postharvest physiological deterioration (PPD) caused by wound. However, the molecular mechanism underlying PPD tolerance remains elusive in cassava. The reactive oxygen species (ROS) scavenging system is activated at the preliminary stage of PPD and peroxidase (POD) can effectively eliminate ROS. The expression level of MePOD12 and POD enzymatic activity in cassava tuberous roots was considerably up-regulated with PPD occurrence. Yeast two-hybrid and luciferase reporter assay showed that MePOD12 physically interacted with lignin-related cinnamyl alcohol dehydrogenase 15 (MeCAD15) in vitro and in vivo. The MePOD12-silenced tuberous roots decayed more than control, especially stored at room temperature for 3 and 5 days after harvesting. The total antioxidant capacity, activities of POD, SOD, CAT, CAD and lignin content were lower than those of control. Particularly, after harvest for 3 days, the accumulation of hydrogen peroxide and superoxide anion substantially increased compared to control. In addition, a proposed model was generated to elaborate the response mechanism of MePOD12 participating in PPD regulation via ROS elimination and lignin accumulation. It provides a new clue for breeding cassava PPD-tolerant varieties.

Cassava(Manihot esculenta)is an important food crop in tropical and subtropical regions.Sugar transporter protein SWEETs facilitate the flow of sugar between cells and play an important role in plant growth and development.In order to clarify the function of SWEET family genes in cassava,cassava'KU50'was used as material in this study,and the gene properties of MeSWEET17b were studied by gene cloning,bioinformatics analysis,subcellular localization,in vitro yeast detection and RT-qPCR,etc.The results were as follows:(1)The open reading frame of MeSWEET17b was 726 bp,encoding 242 amino acids,and located in the plasma membrane.MeSWEET17b had the closer genetic relationship with AtSWEET16 and AtSWEET17,containing 7 transmembrane domains,and belonging to hydrophobic protein.(2)MeSWEET17b mainly transport fructose through the in vitro yeast detection.(3)The results of RT-qPCR showed that the expression trend of MeSWEET17b in stem was basically consistent with in petiole,and the expression was the highest at maturity.The relative expression of MeSWEET177b was relatively low in leaves,and the highest in the expansion stage of tuberous root,while decreased rapidly with the growth of tuberous roots.(4)The'KU50'seedlings were subjected to abiotic stress treatments such as high salt(8 g·L-1 NaCl),drought(100 mmol·L-1 mannitol),oxidation(10％H2O2)and cold(15 ℃ for 24 h,then dropped to 4 ℃ for 24 h).RT-qPCR showed that the relative expressions of MeSWEET17b in leaf and stem had the greatest difference under drought stress.The relative expressions of MeSWEET17b in leaf and fibrous root changed most significantly under salt stress;under oxidation and cold stress,the relative expressions of MeSWEET17b in fibrous root and petiole increased significantly with the extention of treating time.This study provides a theoreticac reference for further studying the function mechanism of sugar transporter protein SWEETs in cassava.

Cassava （Manihot esculenta Crantz） is an important food crop in tropical and subtropical areas. SWEETs participate in a variety of plant activities， including sugar transport， reproduction and development， plant stress， and interaction with pathogens， which plays an important role in plant development. In order to clarify the function of SWEET in the growth and development of cassava， sugar transporter MeSWEET18 was cloned from Cassava South China 9 （SC9） for bioinformatics analysis and verified sugar transport capacity by yeast experiment in this study. The expression trend of MeSWEET18 in cassava in different organ， different developmental stages and under abiotic stress were determined via qRT-PCR method. The results showed that MeSWEET18 contained a 714bp open reading frame （ORF） encoding a protein of 237 amino acids residues with predicted molecular mass of 25.94 kDa and theoretical isoelectric point of 6.57. Through instability index （II） analysis by ProtParam， the instability index （II） of the protein encoded by MeSWEET18 was 37.50， which indicating the protein of MeSWEET18 as stable. MeSWEET18 is a typical membrane protein with a conserved domain MtN3＿slv at the N-terminal and a PQ-Loop Super family conserved domain at the C-terminal and seven transmembrane domains. ProtScale predicted that MeSWEET18 was a hydrophilic protein. Phylogenetic tree analysis revealed that MeSWEET18 belongs to Clade IV. MeSWEET18 was in the same evolutionary tree as AtSWEET16 and AtSWEET17. Alignment of amino acid sequences revealed 53.23% homology between MeSWEET18 and AtSWEET16， and 56.05% homology between MeSWEET18 and AtSWEET17.Yeast functional complementarity tests showed that MeSWEET18 primarily transports fructose. qRT-PCR analysis showed that MeSWEET18 is highly expressed in tuberous roots during the expansion and decreased sharply at maturity of cassava tuberous roots， while the expression levels in leaf， petioles and stems increased with the development of cassava， and reached the maximum at the maturity stage of cassava. qRT-PCR analysis showed that MeSWEET18 was significantly affected by fructose when the hydroponic seedlings of SC9 were treated with sucrose， glucose and fructose solutions under dark conditions. The hydroponic seedlings of SC9 were subjected to abiotic stress including high salt （8g/L NaCl） stress， drought （100mmol/L mannitol） stress， oxidation (10% H 2 O 2 ) stress and low temperature （15℃ for 24h， then reduced to 4℃ for 24h） stress. The results showed that MeSWEET18 is expressed differently in leaf， petioles， stems and roots under abiotic stress. We can speculate that MeSWEET18 plays an important role under abiotic stress in cassava.

As a starchy and edible tropical plant, cassava (Manihot esculenta Crantz) has been widely used as an industrial raw material and a dietary source. However, the metabolomic and genetic differences in specific germplasms of cassava storage root were unclear. In this study, two specific germplasms, M. esculenta Crantz cv. sugar cassava GPMS0991L and M. esculenta Crantz cv. pink cassava BRA117315, were used as research materials. Results showed that sugar cassava GPMS0991L was rich in glucose and fructose, whereas pink cassava BRA117315 was rich in starch and sucrose. Metabolomic and transcriptomic analysis indicated that sucrose and starch metabolism had significantly changing metabolites enrichment and the highest degree of differential expression genes, respectively. Sugar transport in storage roots may contribute to the activities of sugar, which will eventually be exported to transporters (SWEETs), such as (MeSWEET1a, MeSWEET2b, MeSWEET4, MeSWEET5, MeSWEET10b, and MeSWEET17c), which transport hexose to plant cells. The expression level of genes involved in starch biosynthesis and metabolism were altered, which may result in starch accumulation. These results provide a theoretical basis for sugar transport and starch accumulation and may be useful in improving the quality of tuberous crops and increasing yield.

BACKGROUND:Magnesium chelatase plays an important role in photosynthesis, but only a few subunits have been functionally characterized in cassava. RESULTS:Herein, MeChlD was successfully cloned and characterized. MeChlD encodes a magnesium chelatase subunit D, which has ATPase and vWA conservative domains. MeChlD was highly expressed in the leaves. Subcellular localization suggested that MeChlD:GFP was a chloroplast-localized protein. Furthermore, the yeast two-hybrid system and BiFC analysis indicated that MeChlD interacts with MeChlM and MePrxQ, respectively. VIGS-induce silencing of MeChlD resulted in significantly decreased chlorophyll content and reduction the expression of photosynthesis-related nuclear genes. Furthermore, the storage root numbers, fresh weight and the total starch content in cassava storage roots of VIGS-MeChlD plants was significantly reduced. CONCLUSION:Taken together, MeChlD located at the chloroplast is not only required for chlorophyll biosynthesis and photosynthesis, but also affecting the starch accumulation in cassava. This study expands our understanding of the biological functions of ChlD proteins.

Postharvest physiological deterioration (PPD) caused by wounding is one of the main constraints that affect the development of cassava industry. However, the molecular mechanisms underlying the PPD are unknown. In the present study the adaptive response to wound stress was analyzed in combination with transcriptome and metabolome in four kinds of PPD phenomenon from cassava tuberous roots. The results indicated that starch, β-carotene, (-)-epigallocatechin, cyanidin-3-O-glucoside, and L-epicatechin were altered in the wounded tuberous roots. Moreover, the ROS scavenging system was activated at the PPD preliminary stage. Transcriptome analysis further showed that the strongly induced genes were mainly related to carbohydrate metabolism, signal transduction, and polyketide metabolism. Twenty-eight differentially expressed genes (DEGs) in the flavonoid pathway were preferably enriched. The relative quantitative analysis of seventeen genes demonstrated that they were responsive to PPD. Fifty-one differential flavonoid metabolites were detected in widely targeted metabolome profile, among which, luteolin, kaempferol, (-) epicatechin, phloretin, and naringenin were enhanced during PPD. The virus-induced gene silencing of MeCHS3 and MeANR showed that tuberous roots changed tolerance to PPD, and the total flavonoid and anthocyanin contents in leaves were changed. Therefore, the candidate genes and metabolites in flavonoid pathways could participate in PPD regulation. In addition, a proposed model was generated to elaborate the response mechanism of flavonoids under wounding stress, thus providing a future direction for breeding PPD-tolerant cultivars of cassava.

Cassava (Manihot esculenta Crantz) leaves are often used as vegetables in Africa. Anthocyanins possess antioxidant, anti-inflammatory, anti-cancer, and other biological activities. They are poor in green leaves but rich in the purple leaves of cassava. The mechanism of anthocyanin's accumulation in cassava is poorly understood. In this study, two cassava varieties, SC9 with green leaves and Ziyehuangxin with purple leaves (PL), were selected to perform an integrative analysis using metabolomics and transcriptomics. The metabolomic analysis indicated that the most significantly differential metabolites (SDMs) belong to anthocyanins and are highly accumulated in PL. The transcriptomic analysis revealed that differentially expressed genes (DEGs) are enriched in secondary metabolites biosynthesis. The analysis of the combination of metabolomics and transcriptomics showed that metabolite changes are associated with the gene expressions in the anthocyanin biosynthesis pathway. In addition, some transcription factors (TFs) may be involved in anthocyanin biosynthesis. To further investigate the correlation between anthocyanin accumulation and color formation in cassava leaves, the virus-induced gene silencing (VIGS) system was used. VIGS-MeANR silenced plant showed the altered phenotypes of cassava leaves, partially from green to purple color, resulting in a significant increase of the total anthocyanin content and reduction in the expression of MeANR. These results provide a theoretical basis for breeding cassava varieties with anthocyanin-rich leaves.

The 14-3-3 protein family is a highly conservative member of the acid protein family and plays an important role in regulating a series of important biological activities and various signal transduction pathways. The role of 14-3-3 proteins in regulating starch accumulation still remains largely unknown. To investigate the properties of 14-3-3 proteins, the structures and functions involved in starch accumulation in storage roots were analyzed, and consequently, 16 Me14-3-3 genes were identified. Phylogenetic analysis revealed that Me14-3-3 family proteins are split into two groups (ε and non-ε). All Me14-3-3 proteins contain nine antiparallel α-helices. Me14-3-3s-GFP fusion protein was targeted exclusively to the nuclei and cytoplasm. In the early stage of starch accumulation in the storage root, Me14-3-3 genes were highly expressed in high-starch cultivars, while in the late stage of starch accumulation, Me14-3-3 genes were highly expressed in low-starch cultivars. Me14-3-3 I, II, V, and XVI had relatively high expression levels in the storage roots. The transgenic evidence from Me14-3-3II overexpression in Arabidopsis thaliana and the virus-induced gene silencing (VIGS) in cassava leaves and storage roots suggest that Me14-3-3II is involved in the negative regulation of starch accumulation. This study provides a new insight to understand the molecular mechanisms of starch accumulation linked with Me14-3-3 genes during cassava storage root development.

木薯(Manihot esculenta Crantz)属大戟科木薯属热带作物,具有耐干旱贫瘠等特性,木薯叶片富含蛋白质,块根富含淀粉但是缺乏类胡萝卜素,是热带低收入人口的主粮.国家木薯产业技术体系"十三五"期间关于木薯产业问题指出,类胡萝卜素是粮饲化的重要指标,类胡萝卜素也是维生素A的前体物质.本文在前期研究中筛选到与类胡萝卜素生物合成相关转录因子MeGAMYB,MeGAMYB是一种受GA响应的转录因子.为了研究其如何介导GA促进类胡萝卜素生物合成的分子机制,明确其与类胡萝卜素含量及其生物合成途径基因的相关关系,本研究用50 mg/L浓度GA3处理培养40 d的'SC9'茎秆水培苗,在0、3、6、9、12 h取根、茎、叶和叶柄样品检测类胡萝卜生物合成中相关基因的表达情况以及在0、1、2、3、4 d检测类胡萝卜素含量,平行对照用水处理,结果显示:类胡萝卜代谢途径中相关基因以及类胡萝卜素生物合成受GA3诱导,其中叶片在处理4 d时α-胡萝卜素含量最高达到0.19μg/g,是对照的1.2倍;叶片中β-胡萝卜素含量在GA3处理3 d时最高达107.73μg/g,是对照的1.25倍,叶黄素和玉米黄质的含量在处理4 d内都随着GA3处理时间延长含量呈不断增加的趋势.而类胡萝卜素生物合成相关基因如MeLCYB、MeCRTISO、MeZDS、MePDS、MeBCH、MeVDE、MeXAN和MeAAO等和转录因子MeGAMYB的表达量受GA3均上调,其中MeLCYB、MeCRTISO、MePDS、MeBCH、MeAAO和MeXAN等基因的表达趋势与转录因子MeGAMYB的表达趋势一致.本研究可以看出,GA3能促进木薯类胡萝卜素的合成,通过调控类胡萝卜素生物合成相关基因的表达来促进类胡萝卜素的积累,但是具体的调控机制还需要进一步阐释.本结果为研究木薯类胡萝卜素代谢调控机制提供候选功能基因与转录因子,为阐述木薯类胡萝卜素生物合成的机制奠定基础.

糖转运蛋白(sugar will eventually be exported transporter,SWEET)在植物运输糖类、生殖和发育、逆境性、与病原体互作等方面发挥着重要作用.选择木薯糖转运蛋白Mesweet18基因沉默的靶基因区域,通过病毒诱导的基因沉默(virus-induced gene silencing,VIGS)技术注射木薯SC9的盆栽苗叶片.qRT-PCR结果表明,Mesweet18在沉默植株中的表达量显著下调,分别是对照的46.80％、30.23％、21.12％.叶片叶绿素和可溶性糖含量检测结果表明,与对照相比,叶绿素a、b和总含量均出现不同程度的下降,蔗糖和果糖含量显著增加,而葡萄糖含量出现轻微下降.研究Mesweet18在木薯中的分子功能,为深入研究糖转运蛋白SWEET在木薯中的分子机制奠定了基础.

[目的]木薯是世界十亿人的口粮,选育高营养型品种是木薯育种的重要目标之一.通过对白心和黄心糖木薯薯肉代谢物及基因表达分析明确其差异,为高营养型木薯品种改良提供理论依据.[方法]采用超高液相色谱(UPLC)分析薯肉β-胡萝卜素含量,气相色谱质谱联用技术(GC-MS)分析薯肉糖含量,液相色谱质谱联用技术(LC-MS)分析薯肉代谢物,并对差异代谢物进行通路富集分析,采用qRT-PCR对关键基因的表达进行分析.[结果]黄心糖木薯β-胡萝卜素含量、淀粉含量、半乳糖含量、果糖含量显著高于白心木薯,而蔗糖含量和海藻糖含量显著低于白心木薯,葡萄糖含量与白心糖木薯无显著差异.以白心糖木薯为对照,利用代谢组学方法检测到2719种代谢产物,其中267种代谢物发生显著变化,其中黄心糖木薯中上调差异代谢物163个,下调104个,主要涉及能量代谢、脂肪酸代谢、氨基酸代谢、苯丙烷生物合成、淀粉和糖代谢以及类黄酮代谢.267种差异代谢物被注释到74个代谢通路中,其中59种差异代谢物显著或极显著影响18个代谢通路.前10位发生极显著改变的代谢通路分别是亚油酸代谢、α-亚麻酸代谢、ABC转运、丙氨酸、天冬氨酸和谷氨酸代谢、丙酮酸代谢、氨酰tRNA生物合成、氧化磷酸化、碳代谢、乙醛酸和二羧酸代谢和TCA循环.与白心糖木薯相比,黄心糖木薯中淀粉合成相关基因表达上调,淀粉降解相关基因表达下调,β-胡萝卜素合成相关基因均上调.[结论]黄心糖木薯薯肉β-胡萝卜素、淀粉、半乳糖和果糖含量高,而白心糖木薯薯肉中蔗糖和海藻糖含量高.黄心糖木薯脂肪酸代谢途径、淀粉及半乳糖代谢途径、苯丙烷生物合成及类黄酮代谢更活跃,而白心糖木薯氨基酸代谢途径和能量代谢途径更活跃.

As a starchy and edible tropical plant, cassava (Manihot esculenta Crantz) has been widely used as an industrial raw material and dietary source. However, the metabolomic difference in different colors of cassava storage root is unclear. In this study, two specific germplasms WFSR with white flesh of storage root and PFSR with pink flesh of storage root were used as research materials. A previous study found that WFSR was rich in sucrose and fructose, PFSR was rich in starch and glucose. Combined metabolomic and transcriptomic analysis indicated that sucrose and starch metabolism had SCMs enrichment and highest degree of DEGs, respectively. Sugar allocation of storage roots may contribute to sugar transporters SWEETs activities (MeSWEET1a, MeSWEET2b, MeSWEET4, MeSWEET5, MeSWEET10b and MeSWEET17c), which transport hexose in plant cell-to-cell during source-to-sink process. The expression levels of the starch biosynthetic and metabolic genes were altered may result in starch content accumulation. These results provide a theoretical basis for source-to-sink, and then improve quality and increase yield of tuberous crops.

The basic helix-loop-helix (bHLH) proteins are a large superfamily of transcription factors, and play a central role in a wide range of metabolic, physiological, and developmental processes in higher organisms. However, systematic investigation of bHLH gene family in cassava (Manihot esculenta Crantz) has not been reported. In the present study, we performed a genome-wide survey and identified 148 MebHLHs genes were unevenly harbored in 18 chromosomes. Through phylogenetic analyses along with Arabidopsis counterparts, these MebHLHs genes were divided into 19 groups, and each gene contains a similar structure and conserved motifs. Moreover, many cis-acting regulatory elements related to various defense and stress responses showed in MebHLH genes. Interestingly, transcriptome data analyses unveiled 117 MebHLH genes during postharvest physiological deterioration (PPD) process of cassava tuberous roots, while 65 MebHLH genes showed significantly change. Meanwhile, the relative quantitative analysis of 15 MebHLH genes demonstrated that they were sensitive to PPD, suggesting they may involve in PPD process regulation. Cyanogenic glucosides (CGs) biosynthesis during PPD process was increased, silencing of MebHLH72 and MebHLH114 showed that linamarin content was significantly decreased in the leaves. To summarize, the genome-wide identification and expression profiling of MebHLH candidates pave a new avenue for uderstanding their function in PPD and CGs biosynthesis, which will accelerate the improvement of PPD tolerance and decrease CGs content in cassava tuberous roots.

分析α-甘露糖苷酶与木薯块根采后生理变质(PPD)发生的关系,为有效控制木薯PPD发生提供新思路.采用RT-PCR分析α-甘露糖苷酶基因在块根PPD发生过程中的表达模式,ELISA检测α-甘露糖苷酶活性变化.SC9完整薯块储存5 d后开始出现PPD现象,20μmol/L几夫碱喷施木薯块根切片可显著延缓PPD的发生.随着PPD程度的加重,α-甘露糖苷酶活性显著增高,在储存9 d时达到最大值326.24 U/L.MeMNS1、MeMNS4、MeGMII的表达随着PPD过程而逐步增强,且MeGMII表达最显著,采后9 d SC9块根中MeGMII的表达量达到对照的28.05倍,而MeMNS3-1、MeMNS3-2、MeMNS5表达的变化与木薯块根PPD程度间无明显规律.α-甘露糖苷酶参与木薯块根PPD发生的过程,且α-甘露糖苷酶活性与PPD程度呈正相关,其中MeGMII可能是参与此过程的关键基因.

选取14个不同木薯种质的块根放置0～12 d,进行采后生理性腐烂观察,并检测不同时间点β-胡萝卜素的含量.结果显示,木薯块根中β-胡萝卜素含量与其采后生理性腐烂有一定的相关性,即β-胡萝卜素含量相对较高的种质其耐采后腐烂能力相对较强,但是不完全正相关;随着放置天数的增加,抗腐烂能力呈先升高后下降的趋势,其中放置6d时其β-胡萝卜素含量最高,随后块根的腐烂程度加重.

以TM60444和SC9木薯(Manihot esculenta Crantz)组培苗根、茎、叶为材料,采用乙醇:丙酮溶液萃取方法,利用紫外-可见分光光度计对两种木薯组培苗根、茎、叶中的叶绿素和胡萝卜素含量进行了测定,并对类胡萝卜素生物合成相关基因进行了定量分析.结果表明,两个品种叶绿素和胡萝卜素含量都是叶>茎>根;而类胡萝卜素含量是叶>茎≈根.

DNA甲基化在植物的转座子沉默和基因表达调控中起着重要的作用.本研究以淀粉含量差异较大的两个木薯种质SC5和Cas36-12为研究材料,采用甲基化敏感扩增多态性(MSAP)技术,通过LabChip GX Touch微流控毛细管电泳系统分析其块根发育过程中的甲基化变化情况.结果表明:14对选择性扩增引物在SC5和Cas36-12中分别扩增出345和339个甲基化条带,SC5三个发育期的甲基化率高于Cas36-12,且都超过50％.比较SC5和Cas36-12块根发育3个关键时期的甲基化变化情况,发现两份材料甲基化变化的整体趋势是一致的.形成期到膨大期主要以发生甲基化为主;而膨大期到成熟期主要以去甲基化为主.