Domestication syndrome in cassava (Manihot esculenta Crantz): Assessing morphological traits and differentially expressed genes associated with genetic diversity of storage root

Authors: CARVALHO, LUIZ - Embrapa Genetic Resources; Anderson, James; CHEN, SONGBI - Chinese Academy Of Tropical Agricultural Sciences; MBA, CHIKELU - Food & Agriculture Organization (FAO); DOGRAMACI, MUNEVVER - Former ARS Employee

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 9/28/2017
Publication Date: 1/17/2018
Citation: Carvalho, L.J.C.B., Anderson, J.V., Chen, S., Mba, C., Dogramaci, M. 2018. In: Waisundara, V., editor. Cassava. Domestication syndrome in cassava (Manihot esculenta Crantz): Assessing morphological traits and differentially expressed genes associated with genetic diversity of storage root. Rijeka, Croatia. InTech. https://doi.org/10.5772/intechopen.71348.
DOI: https://doi.org/10.5772/intechopen.71348

Interpretive Summary:

Technical Abstract: Cassava is a starchy root crop that provides a staple food source for millions of people in tropical and subtropical regions of Asia, Latin America, and Africa. Brazil is considered the major center of diversification for species of the genus Manihot. It is also a center of domestication for the cultivated species, Manihot esculenta spp esculenta, which is considered to have originated from the ancestral wild species M. esculenta spp flabellifolia. Research efforts directed towards genetic breeding of cassava as a crop is largely dependent on landraces of unknown genetic back ground. Molecular evolution of a crop has relied predominantly on sequence information in order to model the evolutionary history of genes that determine plant speciation and domestication. Molecular phylogenetic technology is a powerful technique used to study genetic traits selected by mankind in crops, which likely led to the proposed “domestication syndrome”. Phylogenetic trees are based on alignment of DNA or protein sequences, from which evolutionary distances between genes can be inferred. However, while a phylogenetic tree models the history of gene duplication events, it does not, by itself, reflect the evolution of gene function. As more is learned about the regulatory and structural complexity that dictates gene/protein function, it is becoming increasingly clear that additional non-sequence information should be considered to predict a more complete understanding of functional evolution. Transcriptional behavior of a gene is poorly represented by sequence data alone but its transcriptional profile may contain critical characteristics of function, including when and where a gene is expressed and the conditions under which gene expression is manifested. These regulatory properties may be crucial in explaining the key functional differences between related genes whose functions cannot be distinguished from sequence alone and, thus, more adequately reflect the functional diversity achieved within gene families across closely related species such as cassava and its ancestor. Microarray technology is one approach for direct, quantitative measurement of transcriptional response to a given environmental or genetic factor, and is a useful experimental source of large-scale gene expression data. The integration of genomic and transcriptomic data is providing an increasingly detailed picture of molecular evolution by incorporating regulatory behavior into models of the evolution of gene expression and function. In this chapter, we describe comprehensive studies related to the wild relative most closely related to cassava ancestor, recognition of natural morphological traits that changed during cassava domestication, and gene expression analysis of cassava storage root variants, which is considered the major trait for domestication of cassava as a crop.