In the first of two greenhouse experiments, mature and immature stem internodes of seven cultivars of E. Re-isolation of PNG40 from intact tissue above the lesion in plants with low lesion severity and no symptoms confirmed endophytic colonization and tolerance to the fungus in the mutants. Among PNG40-inoculated stems, one NCo376 mutant and two N41 mutants showed limited borer (1–2 cm) and % discolored area and the highest % endophyte-colonized stem sections in the internodes immediately above the inoculated ones.
This thesis contains no text, images or tables copied and pasted from the internet unless specifically stated, and the source is described in detail within the thesis and in the References sections. The experimental work described in this thesis was carried out in the Biotechnology Department of the South African Sugarcane Research Institute (SASRI), Mount Edgecombe, Durban, SA from January 2010 to November 2014, under the supervision of Prof. Where the work of others has been used, due acknowledgment is given in the text.
South African Sugarcane Research Institute (SASRI) and the National Research Foundation, South Africa for the financial support. 8 Figure 2: Eldana saccharina injury. a) Frass expelled from a crack in the stem; .. and b) longitudinally split stem revealing feeding larvae and fungi.
Introduction
Literature review
Background and importance of sugarcane
Eldana saccharina
- Nature of damage
- Biology
- Distribution and economic importance
- Control
Insect resistance in sugarcane
Biological control of insect pests
- Endophytes
- Endophyte-mediated biological control of insects
- Fusarium spp. as endophytic biological control agents
Fusarium spp. – Eldana saccharina interactions
Fusarium stem rot
- The pathogen
- The disease
Development of genotypes tolerant to Fusarium spp
- Conventional breeding approaches
- Genetic engineering for resistance
In vitro culture systems
- In vitro culture-induced variation
- Induced mutagenesis
Eldana saccharina (Lepidoptera: Pyralidae) resistance in
In vitro generation of somaclonal variant plants of sugarcane
Potential of Fusarium sacchari-tolerant mutants in controlling Eldana
Transgenic approaches in sugarcane are limited by technological, legislative and marketing challenges (Lakshmanan et al., 2005; Burnquist, 2006; Birch, 2014). Sugarcane belongs to the genus Saccharum L., part of the Andropogoneae tribe of the family Poaceae (grasses) (Azevedo et al., 2011). Pests such as white grubs (Hypopholis sommeri Burm and Schizonycha affinis Boh) (McArthur and Leslie, 2004), the spotted sugarcane stem borer [Chilo sacchariphagus (Bojer) (Lepidoptera:Crambidae)] (Rutherford and Conlong, 2010) and sugarcane thrips [Fulmekiola serrata (Kobus) )] (Way et al., 2010) pose a threat to the South African sugarcane crop.
Bourne, 1961; McFarlane et al., 2009) characterized by reddish-brown discoloration of the bored tissue (Fusarium stem rot) (Fig. 2b). The introduction of resistant varieties into the industry temporarily solved the problem (Atkinson et al., 1981). Lignification of cell walls as the plant matures increases the fiber content of the stem (Gibson et al. 2009) and can lead to increased resistance.
In a study of 12 plant species, Schultz et al. 1993) isolated 16 different endophytic fungal strains from each of 11 species. The genus is identified by the production of three types of asexual spores called conidia (Ohara et al., 2008). Further, transformation of monocots is limited by inefficient transformation systems and low cell competence (Sood et al., 2011).
DNA methylation has also been shown to result in the transposition of genetic elements into genomic DNA (Brown, 1989; Wang et al., 2013). Furthermore, because different genotypes differ in genetic stability, they may differ in susceptibility to mutations (Joyce et al., 2003). Bairu et al. 2006) showed that growth regulators increase somaclonal variation by increasing cell division in bananas.
In such cases, molecular studies are needed to detect variants (Khoddamzadeh et al., 2013; Bello-Bello et al., 2014). UV light induces covalent bonding between neighboring pyrimidines leading to the formation of dimers that alter DNA replication (Waugh et al., 2006). Chemical mutagens used in mutagenesis include hydroxylamine, methyl methanesulfonate (MMS), N-methyl-N-N-nitrosoguanidine (MNNG), ethyl methanesulfonate (EMS), nitric acid and N-methyl-N-nitrosourea (MNU) (Inoue, 2006) ; Shu et al., 2012).
Mutagenesis can be performed using parent material or in vitro cultures (Suprassana et al., 2009). Axillary and adventitious buds, apical meristems (Ahloowalia and Maluszynski, 2001), anthers (Mulwa and Mwanza, 2006) and seeds (Rahman et al., 2013) can be used. Therefore, the generation of double haploids makes mutant selection more efficient (Griffing, 1975; Huang et al., 2014).
RAPDs are widely used to analyze genetic variation in sugarcane (Shahid et al., 2011;
Overview discussion and future prospects
Associations between host plant nitrogen and infestations of the sugarcane borer, Eldana saccharina Walker (Lepidoptera: Pyralidae). Proceedings of the South African of Sugarcane Technologists' Association Sucrose, yield and disease resistance traits of sugarcane varieties tested in the Sussex selection programme. Proceedings of the SAn of Sugarcane Technologists' Association Crop losses due to two sugar cane borers in Reunion and South Africa.
Proceedings of the South African of Sugar Technologists' Association Somatic embryogenesis and the technology of synthetic seeds. Proceedings of the South African of Sugarcane Technologists'. 1998) Phytotoxic effect of culture filtrate from Fusarium subglutinans, the causative agent of fusariosis of pineapple (Ananas comosus (L.) Merr. Proceedings of the South African Sugarcane Technologists' Association Ethyl methanesulfonate (EMS) induced mutation and selection for sugarcane salt tolerance in vitro.
Proceedings of the Association of Sugar Technologists of South Africa Progress in the use of aerially applied Fastac® (alpha-cypermethrin) for the control of the sugarcane borer Eldana saccharina (Lepidoptera: Pyralidae.), and an evaluation of its commercial impact. Preliminary observations on the impact of white-bellied on sugarcane yields in the North Midlands region of the South African sugar industry. 1996) Screening of new sugarcane genotypes for resistance to red rot (Glomerella tucumanensis) Proceedings of the Association of Sugarcane Technologists of South Africa.
Proceedings of the South African Association of Sugarcane Technologists Sugarcane: The crop, the plant, and domestication. Screening of resistance of sugarcane cultivars to Eldanian borer. South African Association of Sugar Technologists Proceedings REN1 is required for the development of microconidia and macroconidia, but not chlamydospores, in the plant pathogenic fungus Fusarium oxysporum. Proceedings of the South African Sugarcane Technologists. 1973) Trends in breeding for disease resistance of crops. 2007).
A preliminary evaluation of the effects of different constant temperatures on the reproduction of Eldana saccharina (Lepidoptera: Pyralidae). Proceedings of the Association of South African Sugarcane Technologists Developmental biology of the immature stages of Eldana saccharina Walker (Lepidoptera: Pyralidae). Proceedings of the Association of Sugar Technologists of South Africa Nitrogen responses and nitrogen use efficiency of four sugarcane varieties in Mpumalanga.
