Hi prosenjit,
In the eyes of the Indian legal system, you and your wife are separate individuals.
If income of an individual exceeds the taxable limit, he or she is obliged or to be more specific it is mandatory as per the income tax act to pay tax and file returns.
Trading in your name or your wife's name does not matter, who operates the account also does not matter.
What matters is the status of the individual as per the income tax act.
Enjoy,
CArnot