JCR | Current advances in pathogen-plant interaction between Verticillium dahliae and cotton provide new insight in the disease management

[Abstract] Verticillium wilt is the second serious vascular wilt caused by the phytopathogenic fungus Verticillium dahliae Kleb. It has distributed worldwide, causing serious yield losses and fiber quality reduction in cotton production. The pathogen has developed different mechanisms like the production of cell wall degrading enzymes, activation of virulence genes and protein effectors to succeed in its infection. Cotton plant has also evolved multiple mechanisms in response to the fungus infection, including a strong production of lignin and callose deposition to strengthen the cell wall, burst of reactive oxygen species, accumulation of defene hormones, expression of defense-related genes, and target-directed strategies like cross-kingdom RNAi for specific virulent gene silencing. This review summarizes the recent progress made over the past two decades in understanding the interactions between cotton plant and the pathogen Verticillium dahliae during the infection process. The review also discusses the achievements in the control practices of cotton verticillium wilt in recent years, including cultivation practices, biological control, and molecular breeding strategies. These studies reveal that effective management strategies are needed to control the disease, while cultural practices and biological control approaches show promising results in the future. Furthermore, the biological control approaches developed in recent years, including antagonistic fungi, endophytic bacteria, and host induced gene silencing strategies provide efficient choices for integrated disease management.

[Title]Current advances in pathogen-plant interaction between Verticillium dahliae and cotton provide new insight in the disease management

[Authors] PALANGA Koffi Kibalou, LIU Ruixian, GE Qun, GONG Juwu, LI Junwen, LU Quanwei, LI Pengtao, YUAN Youlu & GONG Wankui

Journal of Cotton Research 2021, 425


Insights into wing dimorphism in worldwide agricultural pest and host-alternating aphid Aphis gossypii

[Background] The worldwide pest Aphis gossypii has three-winged morphs in its life cycle, namely, winged parthenogenetic female (WPF), winged gynopara (GP), and winged male, which are all produced by a wingless parthenogenetic female (WLPF). Most studies on A. gossypii have focused on WPF, while few have investigated GP and male. The shared molecular mechanism underlying the wing differentiation in the three wing morphs of A. gossypii remains unknown. The wing differentiation of WPF was explored in a previous study. Herein, GP and male were induced indoors. The characters of the body, internal genitals, wing veins, and fecundity of GP and male were compared with those of WPF or WLPF. Compared with WLPF, the shared and separate differentially expressed genes (DEGs) were identified in these three-wing morphs.

[Results] Newly-born nymphs reared in short photoperiod condition (8 L:16D, 18 °C) exclusively produced gynoparae (GPe) and males in adulthood successively, in which the sex ratio was GP biased. A total of 14 GPe and 9 males were produced by one mother aphid. Compared with WLPF, the three-wing morphs exhibited similar morphology and wing vein patterns but were obviously discriminated in the length of fore- and underwings, reproductive system, and fecundity. A total of 37 090 annotated unigenes were obtained from libraries constructed using the four morphs via RNA sequencing (RNA-Seq). In addition, 10 867 and 19 334 DEGs were identified in the pairwise comparison of GP versus WLPF and male versus WLPF, respectively. Compared with WLPF, the winged morphs demonstrated 2 335 shared DEGs (1 658 upregulated and 677 downregulated). The 1 658 shared upregulated DEGs were enriched in multiple signaling pathways, including insulin, FoxO, MAPK, starch and sucrose metabolism, fatty acid biosynthesis, and degradation, suggesting their key roles in the regulation of wing plasticity in the cotton aphid. Forty-four genes that spanned the range of differential expression were chosen to validate statistical analysis based on RNA-Seq through the reverse transcription quantitative real time polymerase chain reaction (RT-qPCR). The comparison concurred with the expression pattern (either up- or downregulated) and supported the accuracy and reliability of RNA-Seq. Finally, the potential roles of DEGs related to the insulin signaling pathway in wing dimorphism were discussed in the cotton aphid.

[Conclusion] The present study established an efficiently standardized protocol for GP and male induction in cotton aphid by transferring newly-born nymphs to short photoperiod conditions (8 L:16D, 18 °C). The external morphological characters, especially wing vein patterns, were similar among WPFs, GPe, and males. However, their reproductive organs were strikingly different. Compared with WLPF, shared (2 335) and exclusively (1 470 in WLPF, 2 419 in GP, 10 774 male) expressed genes were identified in the three-wing morphs through RNA-Seq, and several signaling pathways that are potentially involved in their wing differentiation were obtained, including insulin signaling, starch and sucrose metabolism.

[Title] Insights into wing dimorphism in worldwide agricultural pest and host-alternating aphid Aphis gossypii

[Authors] JI Jichao, HUANGFU Ningbo, LUO Junyu, GAO Xueke, NIU Lin, ZHANG Shuai & CUI Jinjie

Journal of Cotton Research 2021, 45


Toward the efficient use of Beauveria bassiana in integrated cotton insect pest management

[Background] For controlling the resistance to insects, in particular carpophagous and phyllophagous caterpillars, using chemical pesticides has led to contamination of cotton area in Benin. Facing this problem, alternative methods including the use of entomopathogenic fungi as biopesticide could be a sound measure to preserve the environment, biodiversity and ensure good quality of crops. Previous studies have revealed the insecticidal potential of the entomopathogenic Beauveria bassiana on some insect pest species. However, little is known about its effectiveness on cotton Lepidopteran pests. This review is done to learn more about B. bassina for its application in controlling cotton insect pests, especially Lepidopteran species.

[Main body] Different sections of the current review deal with the related description and action modes of B. bassiana against insects, multi-trophic interactions between B. bassiana and plants, arthropods, soil and other microbes, and biological control programs including B. bassiana during last decade. Advantages and constraints in applying B. bassiana and challenges in commercialization of B. bassiana-based biopesticide have been addressed. In this review, emphasis is put on the application methods and targeted insects in various studies with regard to their applicability in cotton

[Conclusion] This review helps us to identify the knowledge gaps related to application of B. bassiana on cotton pest in general and especially in Lepidopteran species in Benin. This work should be supported by complementary laboratory bioassays, station and/or fields experiments for effective management of cotton Lepidopteran pests in Benin.
[Title] Toward the efficient use of Beauveria bassiana in integrated cotton insect pest management

[Authors] DANNON H. Fabrice, DANNON A. Elie, DOURO-KPINDOU O. Kobi, ZINSOU A. Valerien, HOUNDETE A. Thomas, TOFFA-MEHINTO Joëlle, ELEGBEDE I. A. T. Maurille, OLOU B. Dénis & TAMÒ Manuele

Journal of Cotton Research 2020, 324


Transient expression of SbDhr2 and MeHNL in Gossypium hirsutum for herbivore deterrence assay with Spodoptera litura

Journal of Cotton Research

[Background] Spodoptera litura (Lepidoptera: Noctuidae), commonly known as tobacco cutworm or cotton leafworm, is a polyphagous pest which causes considerable damage to cotton (Gossypium hirsutum) and other crops. Herbivore-induced defence response is activated in plants against chewing pests, in which plant secondary metabolites play an important role. Dhurrinase2 (SbDhr2), a cyanogenic β-glucosidase from Sorghum bicolor, is the key enzyme responsible for the hydrolysis of dhurrin (cyanogenic β-glucosidic substrate) to p-hydroxymandelonitrile. Hydroxynitrile lyase (MeHNL) from Mannihot esculanta catalyses the dissociation of cyanohydrins to hydrogen cyanide and corresponding carbonyl compound, both enzymes play a pivotal role in plant defence mechanism.

[Results] SbDhr2 and MeHNL genes were expressed individually and co-expressed transiently in cotton leaves. We examined the feeding response of S. litura to leaves in the choice assay. The Slitura population used in this study showed better feeding deterrence to leaves co-expressing both genes compared with the expression of an individual gene.

[Conclusion] Our results suggest that co-expression of SbDhr2 and MeHNL genes in cotton leaves demonstrate feeding deterrence to S. litura. Engineering cyanogenic pathway in aerial parts of cotton would be an additional defence strategy against generalist pests and can be enhanced against specialist pests.

[Title] Transient expression of SbDhr2 and MeHNL in Gossypium hirsutum for herbivore deterrence assay with Spodoptera litura

[Authors] MAHAJAN Chavi, NASER Rafiuddin & GUPTA Shantikumar



Comparative transcriptional analysis provides insights of possible molecular mechanisms of wing polyphenism induced by postnatal crowding in Aphis gossypii

Aphis gossypii is a worldwide sap-sucking pest with a variety of hosts and a  vector of more than 50 plant viruses. The strategy of wing polyphenism, mostly resulting from population density increasing, contributes to the evolutionary success of this pest. However, the related molecular basis remains unclear. Here, we identified the effects of postnatal crowding on wing morph determination in cotton aphid, and examined the transcriptomic differences between wingless and wing morphs.

Effect of postnatal crowding on wing determination in A. gossypii was evaluated firstly. Under the density of 5 nymphs·cm− 2, no wing aphids appeared. Proportion of wing morphs rised with the increase of density in a certain extent, and peaked to 56.1% at the density of 20 nymphs·cm− 2, and reduced afterwards. Then, transcriptomes of wingless and wing morphs were assembled and annotated separately to identify potentially exclusively or differentially expressed transcripts between these two morphs, in which 3 126 and 3 392 unigenes annotated in Nr (Non-redundant protein sequence) database were found in wingless or wing morphs exclusively. Moreover, 3 187 up- and 1 880 down-regulated genes were identified in wing versus wingless aphid. Pathways analysis suggested the involvement of differentially expressed genes in multiple cellular signaling pathways involved in wing morphs determination, including lipid catabolic and metabolism, insulin, ecdysone and juvenile hormone biosynthesis. The expression levels of related genes were validated by the reverse transcription quantitative real time polymerase chain reaction (RT-qPCR) soon afterwards.

The present study identified the effects of postnatal crowding on wing morphs induction and demonstrated that the critical population density for wing morphs formation in A. gossypii was 20 nymphs·cm− 2. Comparative transcriptome analysis provides transcripts potentially expressed exclusively in wingless or wing morph, respectively. Differentially expressed genes between wingless and wing morphs were identified and several signaling pathways potentially involved in cotton aphid wing differentiation were obtained.


JI Jichao, ZHANG Shuai, LUO Junyu, WANG Li, ZHU Xiangzhen, ZHANG Kaixin, ZHANG Lijuan & CUI Jinjie

Journal of Cotton Research. 2019,2:17


Amino acids application enhances flowers insecticidal protein content in Bt cotton

[Background] Low insecticidal protein expression at reproductive organs affect insect resistance in Bt transgenic cotton. In order to enhance flower insecticidal protein expression, the conventional cultivar Sikang1 (S1) and the hybrid cultivar Sikang3 (S3) were used as experimental materials; the applications of selected 5 types of amino acids and 21 types of amino acids were sprayed on the flowers in 2016 and 2017 cotton growing seasons.

[Results] The flower Bt protein contents increased significantly under the two amino acid treatments in both cultivars, the Bt protein concentration increased by 15.2 to 25.8% compared with the control. However, no significant differences were detected between the two treatments of amino acid application. Increased amino acid and soluble protein contents, enhanced GPT, GOT, protease,and peptidase activities were observed under the amino acid application at the flowering stage.

[Conclusions] These results suggest that exterior application of the amino acids treatments could bolster the flower insecticidal protein expression.

[Authors] TAMBEL Leila. I. M., ZHOU Mingyuan, CHEN Yuan, ZHANG Xiang, CHEN Yuan  and CHEN Dehua

Journal of Cotton Research. 2019; 2:7

Effects of NaCl stress on the biochemical substances in Bt cotton as well as on the growth and development and adult oviposition selectivity of Helicoverpa armigera


Recently, due to the development of food security strategies, cotton has been planted in inland saline-alkali dry soils or in coastal some saline-alkali soils in China. Under the condition, to comprehensively prevent and control Helicoverpa armigera in cotton fields with saline-alkali soils, it is important to study the larval growth and development of H. armigera and to study adult oviposition selectivity in H. armigera adults that feed on NaCl-stressed cotton plants.


In this study, Bt cotton GK19 was used for the experimental group and its nontransgenic parent Simian 3 was used for the control to study the effects of biochemical substances in cotton as well as larval growth and development and adult oviposition selectivity of H. armigera. The experiments were performed by growing cotton indoors under NaCl stress at concentrations of 0 mmol·L− 1, 75 mmol·L− 1 and 150 mmol·L− 1, respectively. The results showed that the expression of Bt protein was significantly inhibited for NaCl-stressed Bt cotton. The content of soluble protein and K+ in the leaves of cotton were decreased, while the content of gossypol and Na+ were increased. In addition, the 5th instar H. armigera larvae exhibited shorten the life span in a 13-day trial period. Under enclosure treatments and at different female densities, the adult oviposition of H. armigera decreased on high NaCl-stressed nontransgenic cotton, while the oviposition on Bt cotton tended to first increase but then decrease under low, moderate and high NaCl stress treatments.


Under certain content ranges of NaCl stress treatments, larval of H. armigera growth and development, and adult oviposition were no significant difference in the change for a certain period. However, under high NaCl stress, larval growth, development and adult oviposition were affected, which may provide insights for the prevention and control of H. armigera for Bt cotton in saline-alkali soils.


Effects of NaCl stress on the biochemical substances in Bt cotton as well as on the growth and development and adult oviposition selectivity of Helicoverpa armigera

LUO Junyu, ZHANG Shuai, ZHU Xiangzhen, JI Jichao, ZHANG Kaixin, WANG Chunyi, ZHANG Lijuan, WANG Li and CUI Jiniie

Journal of Cotton Research. 2019; 2:4




Relative Resistance of Gossypium Species to Insect Complex Under Non-Sprayed Conditions

A number of varieties and strains of Gossypium were grown under non-sprayed conditions to evaluate their relative resistance against insects during two seasons 1993-94 and 1994-95. The strains belonged to Gossypium. Barbadense (Pima), G. palmeri, G. arboreum and G. hirsutum. These varieties had varying degree of resistance to insects. The pima types were highly susceptible to sucking insects and Cotton Leaf Curl Virus. The two entries of G. palmeri exhibited complete tolerance to all sucking insects and Cotton Leaf Curl Virus. Their leaves were lush green, showing no sign of sucking insects injury. The source of resistance in G. palmeri is not known. If this character could be successfully transferred to upland cotton, it may revolutionize cotton production. The potential for substantial saving on insecticides could also lead to reduced environmental pollution. Varieties of G. hirsutum and G. arboreum had a varying but higher degree of resistance against sucking insects, compared to pima types

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Imidcloprid Seed Treatment Effect on Sucking Pests, Predators, Plant Growth and Productivity in Cotton

Imidacloprid seed treatment reduced the jassid populations by 65% in research station studies without affecting predator coccinellids. In farmer participatory trials aimed at area-wide management” of cotton pests during the past two seasons, it reduced jassids by 62-79% and aphids by 66-72% without affecting the predator coccinellids. It also substantially increased plant height (23-30%) up to eight weeks from planting and increased square production (32-49%) during the initial fruiting period. Further, it helped to eliminate foliar sprays against sucking pests in 19 out of 20 farms for 40-50 days. Fields that did not receive seed treatment, required 1-3 foliar sprays to keep the sucking pests under check. This seed treatment, combined with other management tactics employed for area-wide management of cotton pests, resulted in an increase in seed cotton yields by 28-31% over farmer managed fields without seed treatment.

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Chemical Seed Treatments for the Control of Cotton Seedling Pathogens

Seedling diseases of cotton are a very serious problem in Greece because planting starts early in the spring when cold soil and weather conditions favour the development of the disease. The major soil dorne pathogens involved are Pythium ultimatum, Rhizoctonia solani and Thielaviopsis basicola. Cotton seed treatments are designed to protect seed and seedlings from the pathogen complex that cause the seeds, roots and hypocotiyl to rot. Following many years of testing, Vitavex was found to be the most effective against R. solani while two different commercial formulations of metalaxyl (Apron and Ridomil) were found to be effective against P. ultimatum. Black root rot of cotton was significantly reduced when cotton seed was treated with any one of the fungicides Benlate, Bayfidan or Bayleton. Combinations of metalaxyl, benlate and carboxin were found to be effective against damping off caused by all three pathogens. Evaluation of cotton seed treatments in 1994 showed that metalaxyl plus carboxin was the combination that gave the highest final cotton seedling survival. However, the specific pathogen controlled in this trial was R. solani.

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