41 research outputs found
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Not AvailableThe rise of the most appealing genome editing technology i.e. CRISPR/Cas (clustered regularly interspaced short palindromic repeat/CRISPR-associated protein) had stimulated researchers to exploit it for its wide implementation in several eukaryotic organisms along with crop plants. The technology has proven to be highly efficient, economical, easy to use and efficient in precise genome editing. Rice being a primary food crop worldwide has a lot of scope for improvement in terms of its productivity, quality and resistance to environmental stress. The various abiotic and biotic stresses pose a potential threat and are constantly diminishing rice yields globally. After rice genome sequencing, the researchers were engaged in decoding and reading genomes and since then there has been considerable advancement in the improvement of this crop. Moreover, the recent development in different CRISPR/Cas systems has widened its applicability in crops and the research community is very keen on rescripting and editing genomes for a better change. This chapter entails the strategies and protocols for CRISPR mediated genome editing in rice, refined CRISPR systems, recent development and progress of this technology in rice system, all aspects of transgenic development and complications associated with it and its future scope in the improvement of rice crop.Not Availabl
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Not AvailableRice (Oryza sativa L.) is consumed by more than half of the world's population for whom it is the main
source of nutrients and carbohydrates. Rice starch is hydrolyzed by enzymes in the digestive tract and
converted into glucose which is the main energy source for metabolic functions. After meeting the
energy requirement of the body, the extra calories from starch are stored as glycogen or fats for later use.
Therefore, overeating rice with sedentary lifestyle potentially leads to some health problems, such as
obesity, type-II diabetes, and colon diseases in long terms especially in Asian countries. Starch hydrolysis
begins in the mouth with the action of salivary a-amylase and continues in the small intestine with
involvement of other enzymes. However, the resistant starch (RS) which normally comprises < 3% of
cooked rice escapes digestion and therefore, its calories are unavailable for use by cells. RSs are categorized
into five types based on their mechanism of resistance to enzymatic digestion. Rice contains type
5 RS, wherein amylose forms complex with lipids making it more thermostable. The more the RS, the
slower the digestion of rice and the lower is the glycemic index (GI), which is indicative of the ability of
food to raise the blood sugar level. The GI of rice is known to be relatively high compared to other starchy
foods. It was revealed that increased RS content in rice grain is mediated by soluble starch synthase
(SSIIIa), which requires high level expression of granule bound starch synthase (gbssI). In this study,
biochemical analysis was done to determine the GI, RS and amylose content (AC) in rice genotypes from
different ecologies. Large variation in the value of GI (60.07-70.36), RS (0.35-2.57%) and AC (03.79
-23.32%) was observed. Among the genotypes studied, Mahsuri showed lowest GI (60.07) and highest RS
(2.57%). The highest value for GI (70.36) was found in Abhishek with relatively low RS (0.83%).
O. brachyantha had the lowest RS content (0.35%) with relatively high GI (68.84). A significant negative
correlation (R= -0.688) was also observed between GI and RS. Expression analysis of gbssI was carried
out in developing grains of three rice genotypes (Mahsuri, Abhishek and Vandana) differing widely in GI,
RS and AC. There was dramatic increase in the expression levels of the gene in the middle stage of grain
development in all the three genotypes. Maximum expression of the gene was observed in Mahsuri at
middle stage showing a positive correlation between RS content and gbssI expression in the rice cultivars
studied. These findings emphasize upon the need to identify and develop rice genotypes with high RS,
amylose and low GI which may be suitable for consumption by people suffering from diabetes, obesity
and colon diseases.Not Availabl