Gov. Charlie Baker plans to boost state spending next fiscal year by 3.5 percent, making targeted investments while holding the line on many government accounts despite back-to-back years of major jobs gains that are pushing up state tax collections by an estimated 4.3 percent.

With a strong focus on fiscal restraint, Baker’s budget reflects the ongoing reality that fixed costs required for MassHealth, pensions, debt service and other expenses continue to consume large chunks of new revenue, limiting the areas where policy leaders can spend new dollars without turning to taxes or reserves.

The governor’s $39.55 billion spending plan for fiscal 2017, which he intends to file Wednesday, further reduces the volume of one-time revenues in the annual budget to $250 million, down from $1.2 billion in the fiscal 2015 budget that Baker inherited from his predecessor, Gov. Deval Patrick.

The Baker administration plans to roll over between $400 million and $500 million in MassHealth payments, but is not counting those among its one-time revenue sources. And government accounts not targeted for discretionary spending increases or facing rising fixed costs will see an average increase in appropriations of 0.6 percent.

The MBTA will see about a $15 million increase in funding from dedicated sales tax revenues, but the administration said it would commit the same amount of discretionary subsidies – about $187 million – to the agency that it did in last year’s budget. The governor’s spending plan would deliver a total of $1.187 billion to the MBTA.