Variegation : A Signature of Evolution and Survival.

Variegation is often understood simply as the absence or reduction of green pigment (chlorophyll) in certain areas of a plants leaves. These pale or white patches occur when some cells lack chloroplasts, creating striking contrast between green and non-green tissue. This type of variegation, caused by genetic chimeras or tissue-layer mutations, is the most familiar to gardeners and collectors its what gives many houseplants their distinctive marbled or striped leaves.

But beyond these well-known patterns, there are lesser-known stories of variegation born not just from mutations, but from a plants battles with its environment, pathogens, and history.

Many variegated plants started from stress or damage in the past: virus infection, insect attack, or environmental injury. Even after the disease is gone, the signature of that event stays in the plants DNA or protein system. This creates permanent colors and patterns on the leaves.

Some viruses target chloroplasts directly or insert their DNA into the plant genome (in both nucleus and chloroplast). These viruses may no longer spread, but their DNA can still change how the plant works. This makes special colors or patterns.

In nature, variegated plants may grow slower and may be weaker. But sometimes variegation helps survival:
some time leaves look sick so insects avoid eating them , some time proteins made from old virus DNA may give new resistance which didn't express to phenotype.

Humans see beauty in these marks and choose these plants. Many famous variegated plants are actually living records of history, showing how plants fight, adapt, and turn damage into beauty.

by Greenneko.net
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References
1. Zhao J, Zhang X, Hong Y, Liu Y. Chloroplast is a common target of plant viruses for viral pathogenesis or propagation. Front. Microbiol. 2016. Link
2. Caulimoviridae viral DNA integration into plant genomes. Wikipedia
3. Variegation: Defensive masquerade hypothesis. Wikipedia
4. Yu F et al. Variegation mutants and mechanisms of chloroplast biogenesis. Plant J. 2007. ResearchGate