In microalgae, starch can function as a primary carbon storage compound that is accumulated during the day and consumed during the night [ 16, 34].
Granulose is a starch-like storage compound that is accumulated in late exponential/stationary phase prior to sporulation and acts as a carbon and energy source for subsequent endospore formation.
In either case, lipid is an energy-rich storage compound that can be chemically transesterified to produce fatty acid methyl esters (FAME), the biological equivalent to diesel fuel (a.k.a., biodiesel).
Thus, somatic embryos might accumulate storage compounds that are confined to the endosperm in zygotic embryogenesis.
Polyhydroxyalkanoates (PHAs) are highly reduced bacterial storage compounds that are accumulated in most bacteria during unbalanced growth conditions [ 37].
One of these mechanisms may be the accumulation of storage compounds that can be utilized by cells as endogenous carbon sources and electron donors during periods of nutritional scarcity.
In this study, our transcriptomic analysis also revealed new cellular responses which were not observed in the previous proteomic analysis [ 26]: i) Enhanced production of storage compounds: Polyhydroxyalkanoates (PHAs) are common carbon storage compounds that are accumulated during unbalanced growth conditions [ 43].
Some of these molecules may be required for synthesis of storage compounds that act as energy reserves for sclerotia germination [ 21], and the observed increased expression in this study of certain transport protein genes, including those of ABC, MFS, and lipid transport systems, might reflect such a scenario.
Then, the metabolic network was completed by the pathways of seven storage compounds that have also been considered and manually curated in the model: glycogen, α,α-trehalose, PHA such as PHB and PHV [ 10, 28], TAG [ 10, 29, 30], and polyP.
This indicates that the sink cells in sugar cane do not recognise isomaltulose as a storage compound, and thereby signal for increased photosynthesis, sugar transport and sugar loading.
