9 research outputs found
Citrus biotechnology
Agricultural crops that can better withstand the changing climatic and pathogen landscape have been produced through
natural
selection throughout the millennia and, in recent years, through the process of human-assisted plant breeding and
selection. However, a lack of genetic diversity in many commercially cultivated crops (due to monoculture) has made them
more vulnerable to biotic and abiotic stresses (Esquinas-Alcazar, 2005; Keneni et al., 2012). Citrus, belonging to the Rutaceae
family, is one of the most important commercial woody fruit crops in the tropical and subtropical areas of the world. The
origin of citrus is traced back to parts of tropical and subtropical Southeast Asia (Wu et al., 2018). In addition to fresh fruit
and juice, essential oils and pectin are also produced from citrus (Fisher and Phillips, 2008; Davies and Albrigo, 1994). Citrus
products play an important role in human diets as citrus fruits are a rich source of vitamin C and also contain other important
macro- and micronutrients (Ting, 1980). When consumed as a fresh fruit, citrus is a good source of dietary fiber (Marin et al.,
2007). Moreover, citrus fruits are rich in antioxidants (Liu et al., 2012) and citrus flavonoid compounds have anticancer and
antiinflammatory properties (Benavente-Garcia and Castillo, 2008; see Chapter 24 for a detailed description on this subject).
In citrus, despite its wide genetic diversity, large-scale production is restricted to a few cultivars. In the Mediterranean region,
citrus production is restricted to Clementine, blood and other orange, and lemon cultivars (Demirkeser et al., 2009). Similarly
in Japan and Korea, Satsuma mandarins account for the majority in acreage (Choi, 2004; Hong et al., 2007). In Florida, the
cultivars Hamlin and Valencia predominate (Omar et al., 2007; Alva et al., 2003). Citrus has a high cell-to-plant regeneration
capacity via both somatic embryogenesis and organogenesis, making it amenable to numerous biotechnology applications.
Several elite genetically improved citrus rootstock and scion cultivars have been developed in recent years. All these cultivars
have been derived from natural or induced mutations, somaclonal variation, or traditional breeding (Talon and Gmitter, 2008;
Peña and Navarro, 2000; Deng, 2005). The worldwide citrus industry requires new varieties to help overcome barriers to
production and to help create new marketing opportunities. The complex reproductive biology of citrus, including production
of nucellar seedlings, long juvenile periods, and the complex taxonomic relationships among cultivar groups, is one
of the reasons for the low-level impact of conventional breeding in citrus genetic improvement (Talon and Gmitter, 2008).
Biotechnological interventions have been necessary to aid in the rapid germplasm enhancement of existing cultivars (Peña
and Navarro, 2000) and the development of new ones. This chapter will detail the most relevant and important biotechnology
applications and resulting progress toward citrus production and improved cultivar development. Topics covered in the
chapter include: micropropagation (shoot multiplication and rooting); haploid production (gametic embryogenesis); somaclonal
variation and somatic cybridization; transformation; and CRISPR gene editing. Applications of these biotechnologies
are already making significant contributions to improving fruit quality for the fresh market and processing as well as solving
industry threatening disease problems, especially HLB and citrus canker. Emerging biotechnologies continue to expand the
toolbox available for citrus improvement, making it a model system for woody fruit tree crops
Design and application of various visible light responsive metal oxide photocatalysts
The chapter aims to provide a general overview of current thinking and research results regarding the development of visible light responsive metal oxide–based catalysts with enhanced photocatalytic activities, especially outlining their chemical and physical properties, as well as the critical importance of photocatalyst preparation procedure. This chapter will summarize published research literature and their key interpretations, concerning complex interactions that occur during the photocatalyst preparation taking into consideration synthesis methodology, composition, as well as functional properties. Additionally, numerous applications of metal oxide photocatalysts are discussed, especially emphasizing wastewater treatment and clean energy production, highlighting the correlation between their efficiency and recent modifications applied to metal oxides